A208178 Primes of the form 256*k + 1.

257, 769, 3329, 7681, 7937, 9473, 10753, 11777, 12289, 13313, 14081, 14593, 15361, 17921, 18433, 19457, 22273, 23041, 23297, 25601, 26113, 26881, 30977, 31489, 32257, 36097, 36353, 37633, 37889, 39937, 40193, 40961, 41729, 43777, 45569, 46337, 49409, 49921

Offset: 1

Author

Bruno Berselli, Feb 25 2012

Keywords

• nonn
• easy

Comments

Odd primes p such that -1 is a 128th power mod p. - Eric M. Schmidt, Mar 27 2014

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A065091, A002144, A007519, A094407, A133870, A142925, A208177, A076339.

Programs

Haskell

a208178 n = a208178_list !! (n-1)
a208178_list = filter ((== 1) . a010051) [1,257..]
-- Reinhard Zumkeller, Mar 06 2012

Magma

[ p: p in PrimesUpTo(50000) | p mod 256 eq 1 ];

Mathematica

Select[256 Range[195] + 1, PrimeQ]

PARI

for(n=1,195,r=256*n+1; if(isprime(r), print1(r", ")));

Formula

a(n) ~ 128n log n. - Charles R Greathouse IV, Nov 01 2022