A227991 Highest power of 3 dividing prime(n)+1.

3, 1, 3, 1, 3, 1, 9, 1, 3, 3, 1, 1, 3, 1, 3, 27, 3, 1, 1, 9, 1, 1, 3, 9, 1, 3, 1, 27, 1, 3, 1, 3, 3, 1, 3, 1, 1, 1, 3, 3, 9, 1, 3, 1, 9, 1, 1, 1, 3, 1, 9, 3, 1, 9, 3, 3, 27, 1, 1, 3, 1, 3, 1, 3, 1, 3, 1, 1, 3, 1, 3, 9, 1, 1, 1, 3, 3, 1, 3, 1, 3, 1, 27, 1, 1, 3, 9

Offset: 1

Author

Bruno Berselli, Aug 05 2013

Keywords

• nonn

Links

• Bruno Berselli, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A068503 (highest power of 3 dividing prime(n)-1), A068504 (highest power of 2 dividing prime(n)+1), A227990.

Programs

Magma

[3^Valuation(NthPrime(n)+1, 3): n in [1..100]];

Mathematica

Table[3^IntegerExponent[Prime[n] + 1, 3], {n, 100}]

PARI

forprime(p=2, 700, print1(3^valuation(p+1, 3), ", "));

Formula

a(n) = 3^A227990(n).