A027966 T(n, 2*n-4), T given by A027960.

1, 4, 11, 26, 54, 101, 174, 281, 431, 634, 901, 1244, 1676, 2211, 2864, 3651, 4589, 5696, 6991, 8494, 10226, 12209, 14466, 17021, 19899, 23126, 26729, 30736, 35176, 40079, 45476, 51399, 57881, 64956, 72659, 81026, 90094, 99901, 110486, 121889, 134151, 147314, 161421, 176516, 192644

Offset

2,2

Links

G. C. Greubel, Table of n, a(n) for n = 2..1000

Index entries for linear recurrences with constant coefficients, signature (5,-10,10,-5,1).

Formula

From Ralf Stephan, Feb 07 2004: (Start)

G.f.: x^2*(1 - x + x^2 + x^3 - x^4)/(1-x)^5.

Differences of A027967. (End)

From G. C. Greubel, Jun 30 2019: (Start)

a(n) = (n^4 + 2*n^3 - 25*n^2 + 94*n - 96)/24.

E.g.f.: (96 +24*x - (96 - 72*x + 12*x^2 - 8*x^3 - x^4)*exp(x))/24. (End)

Mathematica

LinearRecurrence[{5, -10, 10, -5, 1}, {1, 4, 11, 26, 54}, 50] (* G. C. Greubel, Jun 30 2019 *)

Prog

(PARI) vector(50, n, n++; (n^4+2*n^3-25*n^2+94*n-96)/24) \\ G. C. Greubel, Jun 30 2019
(Magma) [(n^4+2*n^3-25*n^2+94*n-96)/24: n in [2..50]]; // G. C. Greubel, Jun 30 2019
(Sage) [(n^4+2*n^3-25*n^2+94*n-96)/24 for n in (2..50)] # G. C. Greubel, Jun 30 2019
(GAP) List([2..50], n-> (n^4+2*n^3-25*n^2+94*n-96)/24) # G. C. Greubel, Jun 30 2019

Crossrefs

A column of triangle A026998.

Sequence in context: A077270 A076048 A109414 * A141534 A320852 A192961

Adjacent sequences: A027963 A027964 A027965 * A027967 A027968 A027969

Keyword

nonn,easy

Author

Clark Kimberling

Extensions

Terms a(31) onward added by G. C. Greubel, Jun 30 2019

Status

approved