A318678 Sum of deficiencies of deficient divisors of n.

1, 2, 3, 3, 5, 4, 7, 4, 8, 8, 11, 5, 13, 12, 13, 5, 17, 9, 19, 9, 19, 20, 23, 6, 24, 24, 22, 13, 29, 16, 31, 6, 31, 32, 33, 10, 37, 36, 37, 10, 41, 24, 43, 25, 30, 44, 47, 7, 48, 34, 49, 31, 53, 23, 53, 14, 55, 56, 59, 17, 61, 60, 46, 7, 63, 40, 67, 43, 67, 40, 71, 11, 73, 72, 58, 49, 75, 48, 79, 11, 63, 80, 83, 25, 83, 84, 85, 26, 89, 33, 89, 61

Offset

1,2

Links

Antti Karttunen, Table of n, a(n) for n = 1..65537

Index entries for sequences related to sigma(n)

Formula

a(n) = Sum_{d|n} [A033879(d) > 0]*A033879(d).

a(n) = A296075(n) + A318679(n).

Mathematica

f[n_] := 2 n - DivisorSigma[1, n]; Array[DivisorSum[#, f, f@ # >= 0 &] &, 92] (* Michael De Vlieger, Sep 04 2018 *)

Prog

(PARI) A318678(n) = sumdiv(n, d, d=d+d-sigma(d); (d>0)*d);

Crossrefs

Cf. A033879, A187793, A296075, A318441, A318442, A318679.

Sequence in context: A161857 A135533 A296075 * A119674 A064920 A064916

Adjacent sequences: A318675 A318676 A318677 * A318679 A318680 A318681

Keyword

nonn

Author

Antti Karttunen, Sep 04 2018

Status

approved