A224856 Numbers n such that 90*n + 29 and 90*n + 31 are twin primes.

0, 6, 7, 11, 14, 28, 30, 33, 37, 39, 47, 53, 61, 65, 74, 75, 76, 77, 84, 88, 91, 110, 128, 139, 152, 158, 170, 179, 180, 194, 195, 201, 215, 216, 228, 229, 251, 271, 282, 305, 308, 312, 334, 336, 345, 362, 366, 368, 370, 373, 383, 384, 410, 411, 413, 427, 450

Offset: 1

Author

J. W. Helkenberg, Jul 22 2013

Keywords

• nonn
• easy

Crossrefs

Cf. A201739, A201819.

Programs

Maple

a:= proc(n) option remember; local k; for k from 1+
       `if`(n=1, -1, a(n-1)) while not (isprime(29+(90*k))
        and isprime(31+(90*k))) do od; k
    end:
seq(a(n), n=1..100);  # Alois P. Heinz, Jul 23 2013

Mathematica

Select[Range[0, 499], PrimeQ[90# + 29] && PrimeQ[90# + 31] &] (* copied from: Alonso del Arte, Jul 22 2013 *)

Formula

A201739 INTERSECT A201819.