A013602 a(n) = nextprime(4^n)-4^n.

1, 1, 1, 3, 1, 7, 3, 27, 1, 3, 7, 15, 43, 15, 3, 3, 15, 25, 31, 7, 15, 15, 7, 15, 21, 55, 21, 159, 81, 69, 33, 135, 13, 9, 33, 25, 15, 37, 15, 7, 13, 9, 3, 27, 7, 133, 25, 129, 61, 7, 277, 267, 111, 99, 33, 27, 25, 43, 33, 25, 451, 277, 67, 7, 51, 169, 67, 27, 85, 87

Offset: 0

Author

James Kilfiger (mapdn(AT)csv.warwick.ac.uk)

Keywords

• nonn

Links

• Daniel Starodubtsev, Table of n, a(n) for n = 0..1000

Crossrefs

Cf. A000302, A104082.

Programs

Maple

seq(nextprime(4^i)-4^i,i=0..100);

Mathematica

np4[n_]:=Module[{c=4^n},NextPrime[c]-c]; Array[np4,70,0] (* Harvey P. Dale, Jan 23 2012 *)

PARI

a(n) = nextprime(4^n)-4^n; \\ Michel Marcus, Aug 13 2019

Formula

a(n) = A104082(n) - A000302(n). - Michel Marcus, Aug 13 2019

a(n) = A013597(2*n), n >= 0. - A.H.M. Smeets, Aug 13 2019