A337196 The 3-adic valuation of 1+A000265(sigma(n)), where A000265 gives the odd part.

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Offset: 1

Author

Antti Karttunen, Aug 18 2020

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..65537
• Index entries for sequences related to sigma(n)

Crossrefs

Cf. A000203, A000265, A007949, A074941, A161942, A336698, A336700, A337194, A337195.

Cf. A337197 (the first occurrence of each n).

Programs

Mathematica

Array[IntegerExponent[1 + #/2^IntegerExponent[#, 2], 3] &@ DivisorSigma[1, #] &, 105] (* Michael De Vlieger, Feb 22 2021 *)

PARI

A007949(n) = valuation(n,3);
A000265(n) = (n>>valuation(n,2));
A337196(n) = A007949(1+A000265(sigma(n)));

Formula

a(n) = A007949(A337194(n)) = A007949(1+A000265(A000203(n))).

a(n) = A007949(A336698(n)).