A055831 T(n,n-4), where T is the array in A055830.

5, 15, 31, 54, 85, 125, 175, 236, 309, 395, 495, 610, 741, 889, 1055, 1240, 1445, 1671, 1919, 2190, 2485, 2805, 3151, 3524, 3925, 4355, 4815, 5306, 5829, 6385, 6975, 7600, 8261, 8959, 9695, 10470, 11285, 12141, 13039

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 (4,-6,4,-1).

Formula

a(n) = (n-3)*(n^2+6*n-10)/6, n>3.

G.f.: x^4*(5-5*x+x^2)/(1-x)^4. - R. J. Mathar, Mar 13 2016

E.g.f.: (-30 - 6*x + 3*x^2 + (30 - 24*x + 6*x^2 + x^3)*exp(x))/6. - G. C. Greubel, Jan 21 2020

Maple

seq( (n-3)*(n^2+6*n-10)/6, n=4..40); # G. C. Greubel, Jan 21 2020

Mathematica

Table[(n-3)*(n^2+6*n-10)/6, {n, 4, 40}] (* G. C. Greubel, Jan 21 2020 *)

Prog

(PARI) a(n) = (n-3)*(n^2+6*n-10)/6; \\ G. C. Greubel, Jan 21 2020
(Magma) [(n-3)*(n^2+6*n-10)/6: n in [4..40]]; // G. C. Greubel, Jan 21 2020
(Sage) [(n-3)*(n^2+6*n-10)/6 for n in (4..40)] # G. C. Greubel, Jan 21 2020
(GAP) List([4..40], n-> (n-3)*(n^2+6*n-10)/6); # G. C. Greubel, Jan 21 2020

Crossrefs

Cf. A055830.

Sequence in context: A225325 A133268 A056108 * A346823 A037984 A298032

Adjacent sequences: A055828 A055829 A055830 * A055832 A055833 A055834

Keyword

nonn,easy

Author

Clark Kimberling, May 28 2000

Status

approved