A336699 a(n) = A000265(1+A000265(sigma(A000265(n)))), where A000265(k) gives the odd part of k, and sigma is the sum of divisors function.

1, 1, 1, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 1, 1, 5, 7, 3, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 5, 1, 7, 5, 3, 1, 1, 11, 1, 3, 1, 5, 1, 1, 1, 29, 1, 5, 1, 7, 3, 5, 1, 3, 1, 1, 1, 1, 1, 7, 1, 11, 1, 9, 5, 1, 1, 5, 7, 19, 5, 1, 3, 1, 1, 3, 1, 61, 11, 11, 1, 7, 3, 1, 1, 23, 5, 1, 1, 1, 1, 1, 1, 25, 29, 5, 1, 13, 5, 7, 1, 1

Offset

1,9

Comments

See the "lacunae" in the scatter plot. - Antti Karttunen, Mar 27 2022

Links

Antti Karttunen, Table of n, a(n) for n = 1..16384

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

Jon Maiga, Computer-generated formulas for A336699, Sequence Machine.

Index entries for sequences related to sigma(n)

Formula

a(n) = A000265(1+A000265(A000593(n))) = A000265(1+A161942(A000265(n))).

a(n) = A336698(A000265(n)).

From Antti Karttunen, Mar 27 2022: (Start)

a(n) = A351565(A000593(n)).

[The following formulas were discovered by Sequence Machine]:

a(n) = A351565(A002131(n)) = A000265(1+A000265(A002131(n))).

a(n) = A336698(1+A322250(n)).

a(n) = A171435(A000593(n)+A082903(n)).

(End)

Prog

(PARI)
A000265(n) = (n>>valuation(n, 2));
A336699(n) = A000265(1+A000265(sigma(A000265(n))));

Crossrefs

Cf. A000203, A000265, A000593, A002131, A082903, A161942, A171435, A322250, A336698, A336700, A336701, A336844 [= a(A003961(n))], A351565.

Sequence in context: A070672 A319101 A354487 * A239700 A304906 A055061

Adjacent sequences: A336696 A336697 A336698 * A336700 A336701 A336702

Keyword

nonn,look

Author

Antti Karttunen, Aug 02 2020

Status

approved