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A071910
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t(n)*t(n+1)*t(n+2), where t() are the triangular numbers.
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0
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0, 18, 180, 900, 3150, 8820, 21168, 45360, 89100, 163350, 283140, 468468, 745290, 1146600, 1713600, 2496960, 3558168, 4970970, 6822900, 9216900, 12273030, 16130268, 20948400, 26910000, 34222500, 43120350, 53867268, 66758580, 82123650, 100328400, 121777920
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| a(n) = 18*A006542(n+3). - Vladeta Jovovic (vladeta(AT)eunet.rs), Jun 14 2002
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FORMULA
| G.f.: 18*x*(1+3*x+x^2)/(1-x)^7. - Vladeta Jovovic (vladeta(AT)eunet.rs), Jun 14 2002
a(n)=((n+1)(n+2))^3/8 - sum(i=1, n+1, i^3) - Jon Perry (perry(AT)globalnet.co.uk), Feb 13 2004
C(2+n, n)*C(3+n, 1+n)*C(4+n, 2+n) - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jul 29 2005
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CROSSREFS
| Cf. A006542, (first differences of a(n) /18) A006414, (second differences of a(n) /18) A006322, (third differences of a(n) /18) A004068, (fourth differences of a(n) /18) A005891, (fifth differences of a(n) /18) A008706.
Sequence in context: A126920 A022583 A052507 * A121038 A004410 A140325
Adjacent sequences: A071907 A071908 A071909 * A071911 A071912 A071913
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Jun 13 2002
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