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A336691 Number of distinct prime factors of 1+sigma(n). 9
1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 1, 2, 2, 1, 2, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2, 1, 1, 2, 1, 2, 2, 1, 2, 2, 1, 1, 2, 2, 1, 1, 1, 1, 2, 2, 1, 2, 2, 1, 1, 1, 1, 2, 1, 1, 2, 1, 3, 1, 2, 2, 2, 1, 1, 2, 1, 2, 2, 2, 1, 2, 1, 1, 1, 2, 2, 1, 2, 2, 1, 2, 1, 1, 2, 2, 1, 1, 2, 2, 1, 2, 2, 2, 1, 2, 1, 2, 3, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,9
LINKS
FORMULA
a(n) = A001221(1+A000203(n)) = A001221(A088580(n)).
PROG
(PARI) A336691(n) = omega(1+sigma(n));
CROSSREFS
Sequence in context: A353742 A238747 A101873 * A177991 A146289 A214575
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jul 31 2020
STATUS
approved

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Last modified June 17 18:36 EDT 2024. Contains 373463 sequences. (Running on oeis4.)