A013598 a(n) = nextprime(3^n)-3^n.

1, 2, 2, 2, 2, 8, 4, 16, 2, 4, 2, 20, 16, 8, 2, 2, 26, 34, 10, 56, 8, 56, 4, 32, 2, 14, 2, 16, 26, 130, 4, 16, 70, 70, 34, 22, 2, 50, 8, 82, 118, 70, 4, 52, 8, 46, 68, 52, 56, 16, 28, 34, 50, 26, 28, 20, 62, 4, 158, 64, 16, 34, 122, 2, 92, 64, 28, 230, 20

Offset: 0

Author

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

Keywords

• nonn

Links

• Zak Seidov, Table of n, a(n) for n = 0..1000

Crossrefs

Cf. A013604.

Programs

Maple

seq(nextprime(3^i)-3^i,i=0..100);

Mathematica

np[n_]:=Module[{c=3^n},NextPrime[c]-c]; Array[np,80,0] (* Harvey P. Dale, Jul 14 2014 *)

Formula

a(n) = A151800(3^n)-3^n = A013632(3^n). - R. J. Mathar, Nov 28 2016

Extensions

Corrected by Harvey P. Dale, Jul 14 2014