A305117 a(n) = A304651(n)/4.

0, 1, 2, 2, 2, 4, 4, 4, 4, 4, 6, 6, 6, 8, 8, 8, 8, 10, 10, 10, 10, 10, 10, 10, 10, 12, 14, 14, 14, 16, 16, 16, 16, 16, 18, 18, 18, 20, 20, 20, 20, 22, 22, 22, 22, 22, 22, 22, 22, 22, 24, 24, 24, 26, 26, 26, 26, 26, 28, 28, 28, 30, 30, 30, 30, 34, 34, 34, 34, 34, 34

Offset

0,3

Links

Seiichi Manyama, Table of n, a(n) for n = 0..10000

Formula

a(n) = a(n-1) + A000089(n) for n > 0.

Mathematica

a89[n_] := a89[n] = Product[{p, e} = pe; Which[p < 3 && e == 1, 1, p == 2 && e > 1, 0, Mod[p, 4] == 1, 2, Mod[p, 4] == 3, 0, True, a89[p^e]], {pe, FactorInteger[n]}];
a[n_] := a[n] = If[n == 0, 0, a[n-1] + a89[n]];
Table[a[n], {n, 0, 100}] (* Jean-François Alcover, Aug 02 2023 *)

Crossrefs

Cf. A000089, A176562, A304651.

Sequence in context: A362872 A306390 A106160 * A283426 A372057 A340743

Adjacent sequences: A305114 A305115 A305116 * A305118 A305119 A305120

Keyword

nonn

Author

Seiichi Manyama, May 26 2018

Status

approved