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A227990
3^a(n) is the highest power of 3 dividing prime(n)+1.
2
1, 0, 1, 0, 1, 0, 2, 0, 1, 1, 0, 0, 1, 0, 1, 3, 1, 0, 0, 2, 0, 0, 1, 2, 0, 1, 0, 3, 0, 1, 0, 1, 1, 0, 1, 0, 0, 0, 1, 1, 2, 0, 1, 0, 2, 0, 0, 0, 1, 0, 2, 1, 0, 2, 1, 1, 3, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 2, 0, 0, 0, 1, 1, 0, 1, 0, 1, 0, 3, 0, 0, 1, 2
OFFSET
1,7
COMMENTS
This is the 3-adic valuation of prime(n)+1.
LINKS
FORMULA
a(n) = A007949(A008864(n)).
MATHEMATICA
Table[IntegerExponent[Prime[n] + 1, 3], {n, 100}]
PROG
(PARI) forprime(p=2, 700, print1(valuation(p+1, 3), ", "));
(Magma) [Valuation(NthPrime(n)+1, 3): n in [1..100]];
CROSSREFS
Cf. A007949, A008864, A023512 (2-adic valuation of prime(n)+1), A099584 (3-adic valuation of prime(n)-1), A227991 (associated powers of 3).
Sequence in context: A156348 A306437 A343746 * A101614 A051659 A085861
KEYWORD
nonn
AUTHOR
Bruno Berselli, Aug 05 2013
STATUS
approved