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A011898
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[ n(n-1)(n-2)/16 ].
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0
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0, 0, 0, 0, 1, 3, 7, 13, 21, 31, 45, 61, 82, 107, 136, 170, 210, 255, 306, 363, 427, 498, 577, 664, 759, 862, 975, 1096, 1228, 1370, 1522, 1685, 1860, 2046, 2244, 2454, 2677, 2913, 3163, 3427, 3705, 3997, 4305
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,6
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FORMULA
| a(n) = +3*a(n-1) -3*a(n-2) +a(n-3) +a(n-16) -3*a(n-17) +3*a(n-18) -a(n-19). G.f.: x^4*(1+x^2+2*x^6-2*x^7+3*x^8-x^9+x^11+x^12-x^13+x^14) / ( (-1+x)^4*(1+x)*(1+x^2)*(1+x^4)*(1+x^8) ). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 15 2010]
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CROSSREFS
| Sequence in context: A063541 A206246 A171965 * A098577 A004136 A147409
Adjacent sequences: A011895 A011896 A011897 * A011899 A011900 A011901
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KEYWORD
| nonn,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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