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Thursday, September 10, 2026

icky history

I try to keep things family friendly here. Sometimes that is not possible. People often shit and piss themselves when they die, so various warrior cultures developed a tradition of fasting before battle. This has obvious downsides.


Cannibalism of slain enemies was common across Polynesia. If there was nothing left to eat, stealing shit from the guts of a dead warrior was proof you were in the battle.

During WW2 in the Pacific, US troops sometimes took ears, teeth, and other body parts from dead Japanese soldiers as grisly souvenirs.

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In the May 22, 1944 issue of LIFE magazine, a striking and controversial image was featured as the “Picture of the Week.” It showed 20-year-old Natalie Nickerson of Phoenix, Arizona, gazing at a human skull — reportedly of a Japanese soldier — that she had received from her boyfriend, a Navy lieutenant serving in the Pacific
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The Japanese mutilated the dead too. 

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The Ear Mound, or Mimizuka, in Kyoto is a memorial burial mound for the severed noses of Korean and Chinese victims killed during Toyotomi Hideyoshi's invasions of Korea in the late 16th century.
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A plaque, which was later removed, stood in front of the Ear Mound in the 1960s with the passage, "One cannot say that cutting off noses was so atrocious by the standard of the time." Most guidebooks do not mention the Ear Mound, and only a few Japanese or foreign tourists visit the site.[10] The majority of visiting tourists are Korean—Korean tour buses are often seen parked near the Ear Mound.[citation needed]

In 1982, not a single Japanese school textbook mentioned the Ear Mound. 
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But sure, let's all get extra pissed off about Confederate monuments...




Tuesday, September 8, 2026

conjecture: can all primes greater than 2 be written in the form 2n + 3?

All primes greater than 5 end in either 1, 3, 7, or 9. If n is an integer, 2n + 3 will always be odd, but not necessarily prime. If we further require that n not be a multiple of 3, we eliminate all odd multiples of 3 since 2n + 3 will always be a multiple of 3 if n is a multiple of 3. We can also require that n be an integer whose last digit is not 1, because in those cases, 2n + 3 will always have 5 as the last digit. Likewise, if the last digit of n is a 6, the last digit of 2n + 3 will be 5. 

If the conjecture is true, then it makes sense that 1 cannot be written form 2n + 3 since it is not prime. Also, it intuitively makes sense that all other primes would be some combination of the two smallest primes.

Let's make a table

n                            2n + 3                         prime?
0                            3                                  yes
1                            5                                  yes
2                            7                                  yes
4                            11                                yes
5                            13                                yes
7                            17                                yes                 
8                            19                                yes
10                          23                                yes
13                          29                                yes
14                          31                                yes
17                          37                                yes 
19                          41                                yes
20                          43                                yes
22                          47                                yes
23                          49                                no 
25                          53                                yes
28                          59                                yes
29                          61                                yes
32                          67                                yes
34                          71                                yes
35                          73                                yes
37                          77                                no
38                          79                                yes
40                          83                                yes
43                          89                                yes
44                          91                                yes  

For larger primes, we know that because of the possible last digits, the result of subtracting 3 will always be an even number, and so the result can always be written in the form of 2n.                             

I have a hunch I'm missing something but feel I'm on the right track. Could this be a new primality test? It may even be a way to find the next largest prime. It seems the conjecture occasionally returns a perfect square or a semiprime instead of a prime number. 

The largest known prime number is 2^136279841 − 1. That's not really relevant for the conjecture, but I thought I'd put it here. The prime numbers used for RSA and other modern cryptography are in the range of about 2^300, which has roughly 100 digits.

Let's try n = 100,000.

2n + 3 = 200,003

200,003 is prime. 

n = 1,000,000

2n + 3 = 2,000,003

2,000,003 is prime. 

n = 5,000,000,000

2n + 3 = 10,000,000,003

10,000,000,003 = 13 × 769231

Well, looks like I have to think about this some more. 


Saturday, September 5, 2026