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 A142976 a(n) = 5/9 + n^2/2 + 7*n/6 - 4^(n+1) * (2*n/3 + 10/9) + 5*7^(n+1)/9. 3
 1, 39, 546, 5482, 47175, 373809, 2824048, 20729340, 149474205, 1065892555, 7547929806, 53215791774, 374165893891, 2626319535477, 18415017346620, 129036833755984, 903819045351033, 6329115592649775, 44313888005135290, 310239730485553170 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 Index entries for linear recurrences with constant coefficients, signature (18,-120,374,-567,408,-112). FORMULA a(n) = A142458(n+2,n). G.f.: x*(1+21*x-36*x^2-40*x^3) / ((1-7*x)*(4*x-1)^2*(1-x)^3). - R. J. Mathar, Sep 14 2013 MAPLE A142976:=n->5/9 + n^2/2 + 7*n/6 - 4^(n+1) * (2*n/3 + 10/9) + 5*7^(n+1)/9: seq(A142976(n), n=1..25); # Wesley Ivan Hurt, Oct 17 2017 MATHEMATICA Clear[A, a, b, n, m, k]; A[n_, 1] := 1; A[n_, n_] := 1; A[n_, k_] := (3*n - 3*k + 1)A[n - 1, k - 1] + (3*k - 2)A[n - 1, k]; a = Table[A[n, k], {n, 20}, {k, n}]; b = Table[a[[n + m - 1]][[n]], {m, 10}, {n, 10}]; Table[b[[3]][[n]], {n, 10}] CoefficientList[Series[(1 + 21*x - 36*x^2 - 40*x^3)/((1 - 7*x)*(4*x - 1)^2*(1 - x)^3), {x, 0, 25}], x] (* Wesley Ivan Hurt, Oct 17 2017 *) LinearRecurrence[{18, -120, 374, -567, 408, -112}, {1, 39, 546, 5482, 47175, 373809}, 40] (* Vincenzo Librandi, Oct 18 2017 *) PROG (MAGMA) [5/9 + n^2/2 + 7*n/6 - 4^(n+1) * (2*n/3 + 10/9) + 5*7^(n+1)/9: n in [1..25]]; // Wesley Ivan Hurt, Oct 17 2017 CROSSREFS Cf. A142458. Sequence in context: A254871 A193072 A077454 * A200409 A034187 A059609 Adjacent sequences:  A142973 A142974 A142975 * A142977 A142978 A142979 KEYWORD nonn,easy AUTHOR Roger L. Bagula and Gary W. Adamson, Oct 01 2008 STATUS approved

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Last modified October 15 01:40 EDT 2019. Contains 328025 sequences. (Running on oeis4.)