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Search: id:A026832
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| A026832 |
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Number of partitions of n into distinct parts, the least being odd. |
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+0
4
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| 1, 0, 2, 1, 2, 2, 4, 4, 5, 6, 8, 10, 12, 14, 18, 21, 24, 30, 36, 42, 50, 58, 68, 80, 93, 108, 126, 146, 168, 194, 224, 256, 294, 336, 384, 439, 500, 568, 646, 732, 828, 938, 1060, 1194, 1348, 1516, 1704, 1916, 2149, 2408, 2698, 3018, 3372
(list; graph; listen)
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OFFSET
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1,3
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COMMENT
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Fine's numbers L(n).
Also number of partitions of n such that if k is the largest part, then k occurs an odd number of times and each of the numbers 1,2,...,k-1 occurs at least once. Example: a(7)=4 because we have [3,2,1,1],[2,2,2,1],[2,1,1,1,1,1] and [1,1,1,1,1,1,1] - Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 29 2006
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REFERENCES
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N. J. Fine, Basic Hypergeometric Series and Applications, Amer. Math. Soc., 1988; p. 56, Eq. (26.28).
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FORMULA
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G.f.: Sum_{k>=1} ((-1)^(k+1)*(-1+Product_{i>=k} (1+x^i))). - Vladeta Jovovic (vladeta(AT)eunet.rs), Aug 26 2003
G.f.: Sum_{ k >= 1 } x^(k*(k+1)/2)/((1+x^k)*Product_{i=1..k} (1-x^i) ). - Vladeta Jovovic (vladeta(AT)eunet.rs), Aug 10 2004
(1 + Sum_{n >= 1} a(n)q^n )*(1 + 2 Sum_{m>=1} (-1)^m*q^(m^2)) = Sum_{n >= 1} (-1)^n*q^((3*n^2+n)/2)/(1+q^n). [Fine]
G.f.=sum(x^(2k-1)*product(1+x^j, j=2k..infinity), k=1..infinity). - Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 29 2006
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EXAMPLE
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a(7)=4 because we have [7],[6,1],[4,3] and [4,2,1].
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MAPLE
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g:=sum(x^(2*k-1)*product(1+x^j, j=2*k..60), k=1..60): gser:=series(g, x=0, 55); seq(coeff(gser, x^n), n=1..53); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 29 2006
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CROSSREFS
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Cf. A026804, A026805, A026807, A092265, A096661, A097042.
Adjacent sequences: A026829 A026830 A026831 this_sequence A026833 A026834 A026835
Sequence in context: A133770 A163373 A117193 this_sequence A089408 A079318 A050315
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KEYWORD
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nonn,nice
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AUTHOR
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Clark Kimberling (ck6(AT)evansville.edu)
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EXTENSIONS
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More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 29 2006
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