A256776 Primes of form n^2 + 256.

257, 281, 337, 617, 881, 1097, 1217, 1481, 1777, 2281, 2657, 2857, 4481, 5297, 5881, 7481, 8537, 9281, 10457, 12577, 14897, 15881, 17417, 18481, 19577, 23057, 24281, 25537, 26177, 27481, 28817, 30881, 32297, 35977, 38281, 39857, 42281, 44777, 52697, 53617

Offset: 1

Author

Reinhard Zumkeller, Apr 11 2015

Keywords

• nonn

Comments

Conjecture: sequence is infinite.

Links

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

Crossrefs

Cf. A010051, A000290; subsequence of A028916.

Primes of form n^2+b^4, b fixed: A002496 (b=1), A243451 (b=2), A256775 (b=3), A256777 (b=5), A256834 (b=6), A256835 (b=7), A256836 (b=8), A256837 (b=9), A256838 (b=10), A256839 (b=11), A256840 (b=12), A256841 (b=13).

Programs

Haskell

a256776 n = a256776_list !! (n-1)
a256776_list = [x | x <- map (+ 256) a000290_list, a010051' x == 1]

PARI

list(lim)=if(lim<257,return([])); my(v=List(),t); forstep(n=1, sqrtint(lim\1-256), 2, if(isprime(t=n^2+256), listput(v,t))); Vec(v) \\ Charles R Greathouse IV, Aug 18 2017