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A056121
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a(n) = n*(n + 15)/2.
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15
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0, 8, 17, 27, 38, 50, 63, 77, 92, 108, 125, 143, 162, 182, 203, 225, 248, 272, 297, 323, 350, 378, 407, 437, 468, 500, 533, 567, 602, 638, 675, 713, 752, 792, 833, 875, 918, 962, 1007, 1053, 1100, 1148, 1197, 1247, 1298, 1350, 1403, 1457, 1512, 1568, 1625
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OFFSET
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0,2
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LINKS
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FORMULA
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G.f.: x*(8-7*x)/(1-x)^3.
Let f(n,i,a) = Sum_{k=0..n-i} binomial(n,k)*Stirling1(n-k,i)*Product_{j=0..k-1} (-a-j), then a(n) = -f(n,n-1,8), for n>=1. - Milan Janjic, Dec 20 2008
Sum_{n>=1} (-1)^(n+1)/a(n) = 4*log(2)/15 - 52279/540540. - Amiram Eldar, Jan 10 2021
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MAPLE
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a:=n->n*(n+15)/2: seq(a(n), n=0..60);
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MATHEMATICA
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Table[n*(n + 15)/2, {n, 0, 100}] (* Paolo Xausa, Aug 02 2024 *)
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PROG
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(Magma) [n*(n+15)/2: n in [0..60]]; // G. C. Greubel, Jan 18 2020
(Sage) [n*(n+15)/2 for n in (0..60)] # G. C. Greubel, Jan 18 2020
(GAP) List([0..60], n-> n*(n+15)/2 ); # G. C. Greubel, Jan 18 2020
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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