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A213842
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Principal diagonal of the convolution array A213841.
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3
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1, 24, 101, 264, 545, 976, 1589, 2416, 3489, 4840, 6501, 8504, 10881, 13664, 16885, 20576, 24769, 29496, 34789, 40680, 47201, 54384, 62261, 70864, 80225, 90376, 101349, 113176, 125889, 139520, 154101, 169664
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OFFSET
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1,2
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LINKS
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FORMULA
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a(n) = (2*n - 15*n^2 + 16*n^3)/3.
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4).
G.f.: f(x)/g(x), where f(x) = x*(1 + 20*x + 11*x^2) and g(x) = (1-x)^4.
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MATHEMATICA
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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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