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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 Antti Karttunen, Table of n, a(n) for n = 1..65537 Index entries for sequences related to sigma(n) FORMULA a(n) = A001221(1+A000203(n)) = A001221(A088580(n)). PROG (PARI) A336691(n) = omega(1+sigma(n)); CROSSREFS Cf. A000203, A001221, A088580, A058062, A332459, A336692, A336693, A336694, A336695. Sequence in context: A353742 A238747 A101873 * A177991 A146289 A214575 Adjacent sequences: A336688 A336689 A336690 * A336692 A336693 A336694 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.)