doranchak, Subject: Why do the ciphers hate prime numbers? Mon Mar 25, 2013 7:58 am
Response to an interesting observation by Dan Johnson:
http://www.zodiackillerciphers.com/?p=319
traveller1st, Subject: Re: Why do the ciphers hate prime numbers? Mon Mar 25, 2013 9:08 am
Thanks.
Really enjoy these little cipher related reads.
AK Wilks, Subject: Re: Why do the ciphers hate prime numbers? Mon Mar 25, 2013 11:46 am
That is very interesting.
Is there any commonality or pattern to the number sequence, other than lack of primes?
Also, I know you are not usually interested much in anagrams, but looking at the 18 letter unsolved part of the first Zodiac code, there are 9 letters used, and they can form an anangram for :
BOTH PRIME
Along with a thousand other things!
smithy, Subject: Re: Why do the ciphers hate prime numbers? Mon Mar 25, 2013 3:15 pm
Eh???? Yes that’s interesting and…..? Shall we try Fibonacci next?
Yet another statistical anomaly we can pile up with the rest! 
The fact that the "+" signs are a blatant multi-phone might be interesting to discuss. Not where they are, but what they are would be more interesting for me.
Ho hum.
doranchak, Subject: Re: Why do the ciphers hate prime numbers? Mon Mar 25, 2013 3:31 pm
That is very interesting.
Is there any commonality or pattern to the number sequence, other than lack of primes?
Unknown. One way might be to find commonalities between the sequence and entries in the Online Encyclopedia of Integer Sequences:
It could be a very deep rabbit hole to fall into, though. You may return from it resembling Gareth Penn.
Also, I know you are not usually interested much in anagrams, but looking at the 18 letter unsolved part of the first Zodiac code, there are 9 letters used, and they can form an anagram for :
BOTH PRIME
Along with a thousand other things!
More precisely: I am interested in anagrams (because they are fun), but they are not usually useful in the way they are commonly applied to the Zodiac cryptograms.
Also, BOTH PRIME actually re-arranges to BITE MORPH. But I think he would object. 
AK Wilks, Subject: Re: Why do the ciphers hate prime numbers? Mon Mar 25, 2013 3:34 pm
I contend that the + is an L and the 4th line starts as SEE A NAME. If one of you comuter experts would take that as a starting point maybe we could solve the code. Proceed.
AK Wilks, Subject: Re: Why do the ciphers hate prime numbers? Mon Mar 25, 2013 3:42 pm
Sorry doranchal we posted at the same time. Interesting points. Morf were you hunting Zodiac way back in 1969? Apparently you annoyed him.
doranchak, Subject: Re: Why do the ciphers hate prime numbers? Mon Mar 25, 2013 3:58 pm
Side note: There are 68 different prime numbers between 1 and 340. 68 divides evenly into 340: 340 / 5 = 68.
I’d be surprised if Penn didn’t already write about that one.
Perhaps the lack of prime numbers could indicate the use of imaginary numbers in the encoding.
Holmes201,
My take on it.
In a relative short plaintext such as 340 and 408 characters some letters will already be deficient of prime numbers. To these letters then various symbols are mapped in the encoding, and if the letter had few prime numbers to begin with, the symbols are going to have even less. Because multiple symbols (homophones) are assigned to each letter in a cycle. It happens in the 408 as well which uses no imaginary numbers.
Though for the "+" symbol in the 340 it still seems quite unexpected, because of its count.
Holmes201,
My take on it.
In a relative short plaintext such as 340 and 408 characters some letters will already be deficient of prime numbers. To these letters then various symbols are mapped in the encoding, and if the letter had few prime numbers to begin with, the symbols are going to have even less. Because multiple symbols (homophones) are assigned to each letter in a cycle. It happens in the 408 as well which uses no imaginary numbers.
Though for the "+" symbol in the 340 it still seems quite unexpected, because of its count.
You’re are right. We bang our heads trying to figure this cypher.
At the risk of asking a silly question…..How would this prime number aspect play out if Zodiac in encoding this cipher, omitted one or more of the more frequently used letters?
We might have to skew left in this analysis. Changing the weight of the lettering occurrence away from standard measures in english grammatical format. In English the letter E would be expected to be the most used letter in the language. It’s weighting equating to the number of times E is being employed with the highest percentage of frequency. This is not the case though. Skewing the statistics may be of help in solving this code.
