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A001842
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Expansion of Sum_{n>=0} x^(4*n+3)/(1 - x^(4*n+3)).
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12
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0, 0, 0, 1, 0, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 2, 0, 0, 1, 1, 0, 2, 1, 1, 1, 0, 0, 2, 1, 0, 2, 1, 0, 2, 0, 2, 1, 0, 1, 2, 0, 0, 2, 1, 1, 2, 1, 1, 1, 1, 0, 2, 0, 0, 2, 2, 1, 2, 0, 1, 2, 0, 1, 3, 0, 0, 2, 1, 0, 2, 2, 1, 1, 0, 0, 3, 1, 2, 2, 1, 0, 2, 0, 1, 2, 0, 1
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OFFSET
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0,16
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COMMENTS
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Number of divisors of n of form 4*k+3: a(n) = A001227(n) - A001826(n). - Reinhard Zumkeller, Apr 18 2006
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LINKS
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T. D. Noe, Table of n, a(n) for n = 0..10000
Michael Gilleland, Some Self-Similar Integer Sequences
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FORMULA
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a(A072437(n)) = 0. - Benoit Cloitre, Apr 24 2003
G.f.: Sum_{k>=1} x^(3*k)/(1 - x^(4*k)). - Ilya Gutkovskiy, Sep 11 2019
a(n) = Sum_{d|n} (binomial(d,3) mod 2). - Ridouane Oudra, Nov 19 2019
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MAPLE
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with(numtheory): seq(add(binomial(d, 3) mod 2, d in divisors(n)), n=0..100); # Ridouane Oudra, Nov 19 2019
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MATHEMATICA
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Join[{0}, Table[d = Divisors[n]; Length[Select[d, Mod[#, 4] == 3 &]], {n, 100}]] (* T. D. Noe, Aug 10 2012 *)
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CROSSREFS
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Cf. A001227, A001826, A072437.
Sequence in context: A325334 A280287 A147696 * A216654 A326016 A326033
Adjacent sequences: A001839 A001840 A001841 * A001843 A001844 A001845
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane
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STATUS
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approved
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