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

Author

Antti Karttunen, Sep 04 2018

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..65537
• Index entries for sequences related to sigma(n)

Crossrefs

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

Programs

Mathematica

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

PARI

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

Formula

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

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