A337198 - OEIS

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A337198

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

3

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

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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