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A264888
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a(n) = n*(n + 1)*(13*n^2 + 13*n - 14)/24.
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1
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0, 1, 16, 71, 205, 470, 931, 1666, 2766, 4335, 6490, 9361, 13091, 17836, 23765, 31060, 39916, 50541, 63156, 77995, 95305, 115346, 138391, 164726, 194650, 228475, 266526, 309141, 356671, 409480, 467945, 532456, 603416, 681241, 766360, 859215, 960261, 1069966
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OFFSET
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0,3
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COMMENTS
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Partial sum of сentered 13-gonal (or tridecagonal) pyramidal numbers.
This is the case k=13 of the formula n*(n + 1)*(k*n^2 + k*n - 2*k + 12)/24.
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LINKS
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FORMULA
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G.f.: x*(1 + 11*x + x^2)/(1 - x)^5.
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MATHEMATICA
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Table[n (n + 1) (13 n^2 + 13 n - 14)/24, {n, 0, 50}]
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PROG
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CROSSREFS
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Cf. similar sequences listed in A264854.
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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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