A179528 Number of terms of A083207 that are not greater than n.

0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 10, 10, 11, 11, 11, 11, 12, 12, 12, 12, 12, 12, 13, 13, 13, 13, 14, 14, 14, 14, 14, 14, 14, 14, 15, 15, 16, 16, 16, 16, 17, 17, 17, 17

Offset: 1

Author

Reinhard Zumkeller, Jul 19 2010

Keywords

• nonn

Comments

Partial sums of A179527: a(n) = SUM(A179527(k): 1<=k<=n);

A179529(n+1) = a(n+12) - a(n).

Examples

			a(100)=#{6,12,20,24,28,30,40,42,48,54,56,60,66,70,78,80,84,88,90,96}=20;
a(1000000)=229026, by _T. D. Noe_.
		

Links

• R. Zumkeller, Table of n, a(n) for n = 1..10000
• Peter Luschny, Zumkeller Numbers

Programs

Mathematica

ZumkellerQ[n_] := Module[{d = Divisors[n], t, ds, x}, ds = Total[d]; If[Mod[ds, 2] > 0, False, t = CoefficientList[Product[1 + x^i, {i, d}], x]; t[[1 + ds/2]] > 0]];
b[n_] := Boole[ZumkellerQ[n]];
Array[b, 100] // Accumulate (* Jean-François Alcover, Apr 30 2017, after T. D. Noe *)