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Search: id:A028895
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| A028895 |
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5 times triangular numbers. |
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+0
9
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| 0, 5, 15, 30, 50, 75, 105, 140, 180, 225, 275, 330, 390, 455, 525, 600, 680, 765, 855, 950, 1050, 1155, 1265, 1380, 1500, 1625, 1755, 1890, 2030, 2175, 2325, 2480, 2640, 2805, 2975, 3150, 3330, 3515, 3705, 3900, 4100, 4305, 4515, 4730, 4950
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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a(n) = 5/2*n*(n+1). G.f.: A(x) = 5*x/(1-x)^3.
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MAPLE
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[seq(5*binomial(n, 2), n=1..45)]; - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Nov 24 2006
a:=n->sum(2*n+j, j=0..n): seq(a(n), n=0..44); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 29 2007
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CROSSREFS
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Cf. A005891, A046092, A028896.
Sequence in context: A129393 A078905 A059160 this_sequence A010898 A048065 A048021
Adjacent sequences: A028892 A028893 A028894 this_sequence A028896 A028897 A028898
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KEYWORD
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nonn,easy
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AUTHOR
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Joe Keane (jgk(AT)jgk.org)
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