A379379 Sum of odd divisors of n except the "e" odd divisors described in A005279.

1, 1, 4, 1, 6, 1, 8, 1, 13, 6, 12, 1, 14, 8, 19, 1, 18, 1, 20, 1, 32, 12, 24, 1, 31, 14, 40, 1, 30, 1, 32, 1, 48, 18, 41, 1, 38, 20, 56, 1, 42, 1, 44, 12, 49, 24, 48, 1, 57, 31, 72, 14, 54, 1, 72, 1, 80, 30, 60, 1, 62, 32, 95, 1, 84, 1, 68, 18, 96, 41, 72, 1, 74

Offset: 1

Author

Omar E. Pol, Dec 21 2024

Keywords

• nonn

Comments

Shares infinitely many terms with A000593.

a(n) = A000593(n) if n is not in A005279.

a(n) < A000593(n) if n is in A005279.

Crossrefs

Row sums of A379288.

Cf. A001227, A000593, A005279, A182469, A237270, A237271, A237593, A239657, A379374, A379384, A379461.

Programs

Mathematica

a[n_] := Module[{d = Partition[Divisors[n], 2, 1]}, 1 + Total[Select[d, OddQ[#[[2]]] && #[[2]] >= 2*#[[1]] &][[;; , 2]]]]; Array[a, 100] (* Amiram Eldar, Dec 22 2024 *)

Extensions

More terms from Alois P. Heinz, Dec 22 2024