

A179528


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


4



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
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OFFSET

1,12


COMMENTS

Partial sums of A179527: a(n) = SUM(A179527(k): 1<=k<=n);
A179529(n+1) = a(n+12)  a(n).


LINKS

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


EXAMPLE

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.


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 (* JeanFrançois Alcover, Apr 30 2017, after T. D. Noe *)


CROSSREFS

Sequence in context: A111898 A279041 A072746 * A105390 A013941 A061798
Adjacent sequences: A179525 A179526 A179527 * A179529 A179530 A179531


KEYWORD

nonn


AUTHOR

Reinhard Zumkeller, Jul 19 2010


STATUS

approved



