A337198 Number of distinct prime factors in A337194(n) = 1+A000265(sigma(n)), where A000265(k) gives the odd part of k.

1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 1, 2, 1, 1, 1, 2, 2, 1, 1, 2, 1, 1, 1, 2, 1, 2, 2, 1, 1, 2, 2, 1, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 1, 2, 1, 2, 2, 1, 2, 1, 1, 2, 1, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 1, 2, 1, 2, 2, 2, 2, 1, 2, 1, 2, 2, 1, 2, 2, 2, 1, 2, 1, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 1

Offset

1,9

Comments

The first 3 occurs at a(137).

Links

Antti Karttunen, Table of n, a(n) for n = 1..65537

Index entries for sequences related to sigma(n)

Formula

a(n) = A001221(A337194(n)) = 1 + A001221(A336698(n)).

Prog

(PARI)
A000265(n) = (n>>valuation(n, 2));
A337198(n) = (omega(1+A000265(sigma(n))));

Crossrefs

Cf. A000203, A000265, A001221, A161942, A336698, A337194.

Cf. also A058062, A336691, A337199.

Sequence in context: A029884 A309997 A118164 * A099563 A099564 A341356

Adjacent sequences: A337195 A337196 A337197 * A337199 A337200 A337201

Keyword

nonn

Author

Antti Karttunen, Aug 20 2020

Status

approved