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0, 2, 70, 588, 2772, 9438, 26026, 61880, 131784, 257754, 471086, 814660, 1345500, 2137590, 3284946, 4904944, 7141904, 10170930, 14202006, 19484348, 26311012, 35023758, 46018170, 59749032, 76735960, 97569290, 122916222, 153527220, 190242668, 233999782
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listen;
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internal format)
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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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a(n) = (n*(1+2*n)^2*(-3+n+8*n^2+4*n^3))/45. - Colin Barker, Jun 28 2015
G.f.: -2*x*(x^4+28*x^3+70*x^2+28*x+1) / (x-1)^7. - Colin Barker, Jun 28 2015
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EXAMPLE
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n=3: 588 = 2*7*92-4*14^2.
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PROG
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(PARI) concat(0, Vec(-2*x*(x^4+28*x^3+70*x^2+28*x+1)/(x-1)^7 + O(x^100))) \\ Colin Barker, Jun 28 2015
(Python)
def A259317(n): return n*(n*(n**2*(n*(16*n + 48) + 40) - 11) - 3)//45 # Chai Wah Wu, Dec 07 2021
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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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