# [seqfan] Re: A168022

Paolo Lava paoloplava at gmail.com
Fri Nov 30 11:57:52 CET 2012

```Juri,

numbers n such that 4^(n + 1) - 3*2^n + 1 is prime

0, 1, 2, 3, 4, 5, 6, 9, 10, 14, 16, 19, 33, 35, 39, 62, 68, 69, 70, 96,
115, 122, 213, 265, 304, 364, 666, 864, 953, 1448,…

Bye

Paolo

2012/11/25 юрий герасимов <2stepan at rambler.ru>

>
> if
> A168022(non-composite numbers in the eastern ray of the Ulam spiral as
> oriented on the March iover of Scentific American) are 1, 2, 11, 53, 127,
> 233, 541, 743, 977, 1871, 3511,..
> then A_____? = (2^n)-th numbers in the eastem ray of the Ulam spiral as
> oriented on the March iover of Scientific American = 2, 11, 53, 233, 977,
> 4001, 16193, 65153, 261377, 1047041, 4191233, 16771073, 67096577,
> 268410881, 1073692673, 4294868993, 171796725577, 68719083521, 274877120513,
> 1099507957763, 4398043365377, 17592179752961, 70368731594753,
> 281474951544833,...
> or A         ? = (numbers n such that 4^(n + 1) - 3*2^n + 1 is prime) =
>  0, 1, 2, 3, 4, 5, 6, 8, 9, 14, 16, a(11) = ?, a(12) = ?, a(13) = ?  Dear
> Segfans, help calculat the number o this sequence by computer.
> Regards, Juri-Stepan Gerasimov
> ______________________________**_________________
>
> Seqfan Mailing list - http://list.seqfan.eu/
>

```