A379384 Sum of the divisors of n except the "e" divisors described in A005279.

1, 3, 4, 7, 6, 9, 8, 15, 13, 18, 12, 15, 14, 24, 19, 31, 18, 27, 20, 37, 32, 36, 24, 27, 31, 42, 40, 49, 30, 33, 32, 63, 48, 54, 41, 39, 38, 60, 56, 67, 42, 65, 44, 84, 49, 72, 48, 51, 57, 93, 72, 98, 54, 81, 72, 91, 80, 90, 60, 63, 62, 96, 95, 127, 84, 97, 68

Offset: 1

Author

Omar E. Pol, Dec 22 2024

Keywords

• nonn

Comments

Shares infinitely many terms with A000203.

a(n) = A000203(n) if n is not in A005279.

a(n) < A000203(n) if n is in A005279.

Crossrefs

Row sums of A379374.

Cf. A000203, A005279, A237271, A237593, A379288, A379379.

Programs

Mathematica

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

Extensions

More terms from Alois P. Heinz, Dec 22 2024