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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 (list; graph; refs; listen; history; text; internal format)
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
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 (* Jean-François Alcover, Apr 30 2017, after T. D. Noe *)
CROSSREFS
Sequence in context: A111898 A279041 A072746 * A105390 A347941 A013941
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Jul 19 2010
STATUS
approved

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Last modified May 19 12:47 EDT 2024. Contains 372692 sequences. (Running on oeis4.)