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A035592
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Number of partitions of 3n with same number of parts == 1 (mod 3) and == 2 (mod 3).
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1
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1, 2, 6, 14, 32, 66, 134, 256, 480, 868, 1540, 2664, 4536, 7574, 12474, 20234, 32428, 51324, 80388, 124582, 191310, 291114, 439394, 657936, 978054, 1443684, 2117136, 3085174, 4469368, 6437742, 9223324, 13145792, 18644484, 26317916, 36981828
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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FORMULA
| a(n) = A035536(3*n).
G.f.: (Sum_{k>=0} (-1)^k * x^(k * (k + 1)/2)) / (Product_{k>0} 1 - x^k)^3. - Michael Somos, Jul 28 2003
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PROG
| (PARI) {a(n) = if( n<0, 0, polcoeff( sum( k=0, (sqrtint(1 + 8*n) - 1)\2, (-1)^k * x^((k+k^2)/2)) / eta(x + x * O(x^n))^3, n))} /* Michael Somos, Jul 28 2003 */
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CROSSREFS
| Cf. A035536.
Sequence in context: A002524 A188493 A055292 * A096238 A074878 A065495
Adjacent sequences: A035589 A035590 A035591 * A035593 A035594 A035595
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KEYWORD
| nonn,changed
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AUTHOR
| Olivier Gerard (olivier.gerard(AT)gmail.com)
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EXTENSIONS
| More terms from David W. Wilson (davidwwilson(AT)comcast.net)
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