A344765 a(n) = sigma(n) - A011772(n).

0, 0, 2, 0, 2, 9, 2, 0, 5, 14, 2, 20, 2, 17, 19, 0, 2, 31, 2, 27, 26, 25, 2, 45, 7, 30, 14, 49, 2, 57, 2, 0, 37, 38, 34, 83, 2, 41, 44, 75, 2, 76, 2, 52, 69, 49, 2, 92, 9, 69, 55, 59, 2, 93, 62, 72, 62, 62, 2, 153, 2, 65, 77, 0, 59, 133, 2, 110, 73, 124, 2, 132, 2, 78, 100, 84, 75, 156, 2, 122, 41, 86, 2, 176, 74, 89

Offset

1,3

Links

Antti Karttunen, Table of n, a(n) for n = 1..16384

Antti Karttunen, Data supplement: n, a(n) computed for n = 1..65537

Index entries for sequences related to sigma(n)

Formula

a(n) = A000203(n) - A011772(n).

a(n) = A001065(n) + A344763(n).

a(n) = Sum_{d|n} A344768(d).

a(n) = A344769(n) - A294898(n).

Mathematica

A011772[n_] := Module[{m = 1}, While[Not[IntegerQ[m(m+1)/(2n)]], m++]; m];
a[n_] := DivisorSigma[1, n] - A011772[n];
Array[a, 100] (* Jean-François Alcover, Jun 12 2021 *)

Prog

(PARI) A344765(n) = (sigma(n) - A011772(n));

Crossrefs

Cf. A000203, A001065, A011772, A294898, A344763, A344766, A344768 (Möbius transform), A344769.

Sequence in context: A212026 A246003 A242052 * A259356 A137302 A324305

Adjacent sequences: A344762 A344763 A344764 * A344766 A344767 A344768

Keyword

nonn

Author

Antti Karttunen, May 30 2021

Status

approved