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 A256857 a(n) = n*(n^2 + 3*n - 2)/2. 0
 0, 1, 8, 24, 52, 95, 156, 238, 344, 477, 640, 836, 1068, 1339, 1652, 2010, 2416, 2873, 3384, 3952, 4580, 5271, 6028, 6854, 7752, 8725, 9776, 10908, 12124, 13427, 14820, 16306, 17888, 19569, 21352, 23240, 25236, 27343, 29564, 31902, 34360 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS The sequence is the 5th upper diagonal of the array in A139600. LINKS Eric Weisstein's World of Mathematics, Polygonal Number Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1). FORMULA G.f.: x*(1 + 4*x -2*x^2)/(1 - x)^4. a(n) = A057145(n+6,n). - R. J. Mathar, Jul 28 2016 a(n) = Sum_{i=1..n} (n-i-1) mod (n+1). - Wesley Ivan Hurt, Sep 15 2017 MATHEMATICA Table[n (n^2 + 3 n - 2)/2, {n, 0, 40}] PROG (MAGMA) [n*(n^2+3*n-2)/2: n in [0..50]]; // Vincenzo Librandi, Apr 14 2015 (PARI) vector(50, n, n--; n*(n^2+3*n-2)/2) \\ Bruno Berselli, Apr 15 2015 CROSSREFS Cf. A139600. Sequence in context: A064225 A304844 A054275 * A122655 A280231 A212972 Adjacent sequences:  A256854 A256855 A256856 * A256858 A256859 A256860 KEYWORD nonn,easy AUTHOR Luciano Ancora, Apr 11 2015 STATUS approved

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Last modified July 18 21:25 EDT 2019. Contains 325144 sequences. (Running on oeis4.)