A324830 Number of divisors d of n such that A323243(d) is a multiple of 3.

1, 1, 2, 1, 1, 3, 2, 1, 3, 1, 1, 4, 2, 3, 3, 2, 1, 4, 2, 1, 4, 2, 1, 5, 1, 3, 4, 4, 2, 4, 1, 2, 3, 1, 3, 5, 2, 3, 4, 1, 1, 6, 2, 2, 5, 1, 1, 7, 3, 1, 3, 4, 2, 6, 1, 5, 4, 3, 1, 5, 2, 2, 6, 2, 3, 6, 1, 1, 3, 5, 2, 7, 1, 3, 4, 4, 3, 6, 2, 2, 5, 1, 1, 8, 2, 3, 4, 3, 2, 7, 4, 1, 3, 2, 3, 8, 1, 5, 5, 2, 2, 5, 1, 5, 7

Offset

1,3

Links

Antti Karttunen, Table of n, a(n) for n = 1..10000 (based on Hans Havermann's factorization of A156552)

Index entries for sequences related to binary expansion of n

Index entries for sequences computed from indices in prime factorization

Index entries for sequences related to sigma(n)

Formula

a(n) = A000005(n) - (A324831(n) + A324832(n)).

For all n >= 1, a(A000040(n)) = 2-A000035(n).

Prog

(PARI) A324830(n) = sumdiv(n, d, (0==(A323243(d))%3));

Crossrefs

Cf. A000005, A156552, A323243, A324831, A324832.

Sequence in context: A345033 A329359 A235682 * A141110 A325758 A280073

Adjacent sequences: A324827 A324828 A324829 * A324831 A324832 A324833

Keyword

nonn

Author

Antti Karttunen, Mar 16 2019

Status

approved