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A058696
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Number of ways to partition 2n into positive integers.
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7
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1, 2, 5, 11, 22, 42, 77, 135, 231, 385, 627, 1002, 1575, 2436, 3718, 5604, 8349, 12310, 17977, 26015, 37338, 53174, 75175, 105558, 147273, 204226, 281589, 386155, 526823, 715220, 966467, 1300156, 1741630, 2323520, 3087735, 4087968
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| Euler transform of period 16 sequence [2,2,3,2,3,1,2,1,2,1,3,2,3,2,2,1,...]. - Michael Somos, Apr 25 2003
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MAPLE
| with(combinat): with(numtheory): a := proc(n) c := 1: l := sort(convert(divisors(n), list)): for i from 1 to nops(l) do c := numbpart(l[i]*2) od: RETURN(c): end: for j from 0 to 61 do printf(`%d, `, a(j)) od: - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 14 2007
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PROG
| (PARI) a(n)=if(n<0, 0, polcoeff(1/eta(x+O(x^(2*n+1))), 2*n))
(Mupad) combinat::partitions::count(2*i) $i=0..54 - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 16 2007
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CROSSREFS
| a(n)=A000041(2n). Cf. A058695.
Sequence in context: A049936 A058358 A135119 * A134508 A091357 A129715
Adjacent sequences: A058693 A058694 A058695 * A058697 A058698 A058699
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Dec 31 2000
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