A369915 a(n) = Sum_{p|n, p prime} lcm(p, n/p) / p.

0, 1, 1, 1, 1, 5, 1, 2, 1, 7, 1, 7, 1, 9, 8, 4, 1, 11, 1, 9, 10, 13, 1, 14, 1, 15, 3, 11, 1, 31, 1, 8, 14, 19, 12, 13, 1, 21, 16, 18, 1, 41, 1, 15, 14, 25, 1, 28, 1, 27, 20, 17, 1, 33, 16, 22, 22, 31, 1, 47, 1, 33, 16, 16, 18, 61, 1, 21, 26, 59, 1, 26, 1, 39, 28, 23, 18

Offset

1,6

Links

Table of n, a(n) for n=1..77.

Index entries for sequences related to lcm's

Formula

a(p^k) = p^(k-2+floor(1/k)) for p prime and k>=1. - Wesley Ivan Hurt, Jul 09 2025

Mathematica

Table[DivisorSum[n, LCM[#, n/#]/# &, PrimeQ[#] &], {n, 100}]

Crossrefs

Cf. A332619, A345266, A345302.

Sequence in context: A202352 A115038 A231990 * A010131 A176323 A260821

Adjacent sequences: A369912 A369913 A369914 * A369916 A369917 A369918

Keyword

nonn,easy

Author

Wesley Ivan Hurt, Feb 05 2024

Status

approved