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 A264888 a(n) = n*(n + 1)*(13*n^2 + 13*n - 14)/24. 1
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS 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. LINKS OEIS Wiki, Figurate numbers Eric Weisstein's World of Mathematics, Pyramidal Number Index entries for linear recurrences with constant coefficients, signature (5,-10,10,-5,1). FORMULA G.f.: x*(1 + 11*x + x^2)/(1 - x)^5. a(n) = Sum_{k = 0..n} A062025(k). MATHEMATICA Table[n (n + 1) (13 n^2 + 13 n - 14)/24, {n, 0, 50}] PROG (PARI) a(n)=n*(n+1)*(13*n^2+13*n-14)/24 \\ Charles R Greathouse IV, Jul 26 2016 CROSSREFS Cf. A062025. Cf. similar sequences listed in A264854. Sequence in context: A027997 A284844 A258724 * A272964 A232579 A212862 Adjacent sequences:  A264885 A264886 A264887 * A264889 A264890 A264891 KEYWORD nonn,easy AUTHOR Ilya Gutkovskiy, Nov 27 2015 STATUS approved

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Last modified May 21 03:23 EDT 2019. Contains 323434 sequences. (Running on oeis4.)