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

Author

Clark Kimberling, May 28 2000

Keywords

• nonn
• easy

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).

Crossrefs

Cf. A055830.

Programs

GAP

List([4..40], 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

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 *)

PARI

a(n) = (n-3)*(n^2+6*n-10)/6; \\ 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

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