A027969 a(n) = T(n, 2*n-7), T given by A027960.

3, 7, 18, 47, 120, 291, 661, 1404, 2801, 5283, 9484, 16305, 26990, 43215, 67191, 101782, 150639, 218351, 310614, 434419, 598260, 812363, 1088937, 1442448, 1889917, 2451243, 3149552, 4011573, 5068042, 6354135, 7909931, 9780906, 12018459, 14680471, 17831898, 21545399, 25902000, 30991795

Offset

4,1

Links

G. C. Greubel, Table of n, a(n) for n = 4..1000

Index entries for linear recurrences with constant coefficients, signature (8,-28,56,-70,56,-28,8,-1).

Formula

From Ralf Stephan, Feb 07 2004: (Start)

G.f.: x^4*(3-2x)*(1-x+x^2)*(1-4x+7x^2-4x^3+x^4)/(1-x)^8.

First differences of A027970. (End)

From G. C. Greubel, Jul 01 2019: (Start)

a(n) = (90720 -85548*n +38822*n^2 -10136*n^3 +1505*n^4 -77*n^5 -7*n^6 + n^7)/5040.

E.g.f.: (-90720 - 35280*x - 7560*x^2 - 1680*x^3 + (90720 - 55440*x + 17640*x^2 - 3360*x^3 + 630*x^4 - 42*x^5 + 14*x^6 + x^7)*exp(x))/5040. (End)

Mathematica

Table[(90720 -85548*n +38822*n^2 -10136*n^3 +1505*n^4 -77*n^5 -7*n^6 + n^7)/5040, {n, 4, 50}] (* G. C. Greubel, Jul 01 2019 *)

Prog

(PARI) for(n=4, 50, print1((90720 -85548*n +38822*n^2 -10136*n^3 +1505*n^4 -77*n^5 -7*n^6 + n^7)/5040, ", ")) \\ G. C. Greubel, Jul 01 2019
(Magma) [(90720 -85548*n +38822*n^2 -10136*n^3 +1505*n^4 -77*n^5 -7*n^6 + n^7)/5040: n in [4..50]]; // G. C. Greubel, Jul 01 2019
(Sage) [(90720 -85548*n +38822*n^2 -10136*n^3 +1505*n^4 -77*n^5 -7*n^6 + n^7)/5040 for n in (4..50)] # G. C. Greubel, Jul 01 2019
(GAP) List([4..50], n-> (90720 -85548*n +38822*n^2 -10136*n^3 +1505*n^4 -77*n^5 -7*n^6 + n^7)/5040) # G. C. Greubel, Jul 01 2019

Crossrefs

A column of triangle A027011.

Sequence in context: A026107 A372033 A173765 * A027971 A219233 A211276

Adjacent sequences: A027966 A027967 A027968 * A027970 A027971 A027972

Keyword

nonn

Author

Clark Kimberling

Extensions

Terms a(35) onward added by G. C. Greubel, Jul 01 2019

Status

approved