[seqfan] Re: 4xy + 6x - 1

[Bob Selcoe]

Hello,

127.  The sequence will be 2 and the Mersenne primes.  The equation is 
2x(2y+3)-1, which is all the even numbers times all the odd numbers minus 1. 
These are all the odd numbers except 2^n-1 which, when prime, are the 
Mersennes.

Best,
Bob Selcoe

--------------------------------------------------
From: "юрий герасимов" <2stepan at rambler.ru>
Sent: Thursday, February 19, 2015 8:55 AM
To: <seqfan at list.seqfan.eu>
Subject: [seqfan] 4xy + 6x - 1

>
> Dear SeqFans,
> Primes not of the form 4xy + 6x - 1: 2, 3, 7, 31, ...
>
> What in the next one?
>
> Thanks. JSG
>
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