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A001877
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Number of divisors of n of form 5k+2.
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5
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0, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 2, 0, 2, 0, 1, 1, 1, 0, 1, 1, 2, 0, 2, 0, 1, 1, 2, 0, 1, 0, 2, 0, 2, 1, 2, 1, 1, 0, 1, 0, 3, 0, 2, 0, 1, 1, 2, 1, 1, 1, 2, 0, 2, 0, 2, 1, 1, 0, 2, 0, 2, 1, 2, 0, 2, 1, 2, 0, 2, 0, 3, 0, 2, 0, 1, 2, 1, 0, 1, 1, 2, 0, 4, 1, 1, 1
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OFFSET
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0,13
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LINKS
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T. D. Noe, Table of n, a(n) for n = 0..10000
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FORMULA
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G.f.: Sum x^(5n+2)/(1-x^(5n+2)), n=0..inf.
G.f.: sum(n>=1, x^(2*n)/(1-x^(5*n))) - Joerg Arndt, Jan 30 2011
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MATHEMATICA
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Join[{0}, Table[d = Divisors[n]; Length[Select[d, Mod[#, 5] == 2 &]], {n, 100}]] (* T. D. Noe, Aug 10 2012 *)
Table[Count[Divisors[n], _?(Mod[#, 5]==2&)], {n, 0, 90}] (* Harvey P. Dale, May 20 2017 *)
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CROSSREFS
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Sequence in context: A219490 A277142 A240592 * A112712 A026608 A264049
Adjacent sequences: A001874 A001875 A001876 * A001878 A001879 A001880
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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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