A331286 Odd part of number of divisors of primorial inflation of n: a(n) = A000265(A329605(n)).

1, 1, 1, 3, 1, 3, 1, 1, 9, 3, 1, 1, 1, 3, 9, 5, 1, 3, 1, 1, 9, 3, 1, 5, 27, 3, 1, 1, 1, 3, 1, 3, 9, 3, 27, 15, 1, 3, 9, 5, 1, 3, 1, 1, 1, 3, 1, 3, 81, 9, 9, 1, 1, 5, 27, 5, 9, 3, 1, 15, 1, 3, 1, 7, 27, 3, 1, 1, 9, 9, 1, 9, 1, 3, 3, 1, 81, 3, 1, 3, 25, 3, 1, 15, 27, 3, 9, 5, 1, 5, 81, 1, 9, 3, 27, 7, 1, 27, 1, 45, 1, 3, 1, 5, 3

Offset

1,4

Links

Antti Karttunen, Table of n, a(n) for n = 1..10000

Antti Karttunen, Data supplement: n, a(n) computed for n = 1..65537

Formula

a(n) = A000265(A329605(n)).

a(n) = A212181(A108951(n)).

Prog

(PARI) A331286(n) = if(1==n, 1, my(f=factor(n), e=1, m=1); forstep(i=#f~, 1, -1, e += f[i, 2]; m *= (e>>valuation(e, 2))^(primepi(f[i, 1])-if(1==i, 0, primepi(f[i-1, 1])))); (m));

Crossrefs

Cf. A000265, A108951, A212181, A329605.

Cf. also A322865.

Sequence in context: A128218 A010283 A134699 * A272880 A003636 A353415

Adjacent sequences: A331283 A331284 A331285 * A331287 A331288 A331289

Keyword

nonn

Author

Antti Karttunen, Jan 14 2020

Status

approved