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A236770
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a(n) = n*(n + 1)*(3*n^2 + 3*n - 2)/8.
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11
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0, 1, 12, 51, 145, 330, 651, 1162, 1926, 3015, 4510, 6501, 9087, 12376, 16485, 21540, 27676, 35037, 43776, 54055, 66045, 79926, 95887, 114126, 134850, 158275, 184626, 214137, 247051, 283620, 324105, 368776, 417912, 471801, 530740, 595035, 665001, 740962
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OFFSET
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0,3
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COMMENTS
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LINKS
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FORMULA
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G.f.: x*(1 + 7*x + x^2)/(1 - x)^5.
a(n) = a(-n-1) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5).
Sum_{n>=1} 1/a(n) = 2 + 4*sqrt(3/11)*Pi*tan(sqrt(11/3)*Pi/2) = 1.11700627139319... . - Vaclav Kotesovec, Apr 27 2016
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MATHEMATICA
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Table[n (n + 1) (3 n^2 + 3 n - 2)/8, {n, 0, 40}]
LinearRecurrence[{5, -10, 10, -5, 1}, {0, 1, 12, 51, 145}, 40] (* Harvey P. Dale, Aug 22 2016 *)
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PROG
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(PARI) for(n=0, 40, print1(n*(n+1)*(3*n^2+3*n-2)/8", "));
(Magma) [n*(n+1)*(3*n^2+3*n-2)/8: n in [0..40]];
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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