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 A256646 26-gonal pyramidal numbers: a(n) = n*(n+1)*(8*n-7)/2. 2
 0, 1, 27, 102, 250, 495, 861, 1372, 2052, 2925, 4015, 5346, 6942, 8827, 11025, 13560, 16456, 19737, 23427, 27550, 32130, 37191, 42757, 48852, 55500, 62725, 70551, 79002, 88102, 97875, 108345, 119536, 131472, 144177, 157675, 171990, 187146, 203167, 220077 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS See comments in A256645. This sequence is related to A051866 by a(n) = n*A051866(n) - Sum_{i=0..n-1} A051866(i). [Bruno Berselli, Apr 09 2015] REFERENCES E. Deza and M. M. Deza, Figurate numbers, World Scientific Publishing (2012), page 93 (24th row of the table). LINKS Luciano Ancora, Table of n, a(n) for n = 0..1000 Luciano Ancora, Polygonal and Pyramidal numbers, Section 3. Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1). FORMULA G.f.: x*(1 + 23*x)/(1 - x)^4. a(n) = A000292(n) + 23*A000292(n-1). MATHEMATICA Table[n (n + 1) (8 n - 7)/2, {n, 0, 40}] LinearRecurrence[{4, -6, 4, -1}, {0, 1, 27, 102}, 40] (* Vincenzo Librandi, Apr 08 2015 *) PROG (MAGMA) [n*(n+1)*(8*n-7)/2: n in [0..50]]; // Vincenzo Librandi, Apr 08 2015 CROSSREFS Partial sums of A255185. Cf. similar sequences listed in A237616. Cf. A000292, A051866. Sequence in context: A197619 A033659 A010015 * A323034 A031429 A154377 Adjacent sequences:  A256643 A256644 A256645 * A256647 A256648 A256649 KEYWORD nonn,easy AUTHOR Luciano Ancora, Apr 07 2015 STATUS approved

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Last modified February 19 18:20 EST 2019. Contains 320324 sequences. (Running on oeis4.)