A028358 Partial sums of A028357.

1, 4, 10, 20, 33, 48, 64, 82, 103, 128, 156, 186, 217, 250, 286, 326, 369, 414, 460, 508, 559, 614, 672, 732, 793, 856, 922, 992, 1065, 1140, 1216, 1294, 1375, 1460, 1548, 1638, 1729, 1822, 1918, 2018, 2121

Offset

0,2

Links

Table of n, a(n) for n=0..40.

Index entries for linear recurrences with constant coefficients, signature (3,-3,0,3,-3,1).

Formula

G.f.: ( -1-x-x^2-2*x^3 ) / ( (1+x)*(x^2-x+1)*(x-1)^3 ). - R. J. Mathar, Dec 15 2015

a(n) = (9 + 72*n + 30*n^2 + 32*cos((n + 1)*Pi/3) - (-1)^n)/24. - Greg Dresden, Jun 22 2021

Mathematica

LinearRecurrence[{3, -3, 0, 3, -3, 1}, {1, 4, 10, 20, 33, 48}, 50] (* Harvey P. Dale, Jun 14 2021 *)
Table[(9 + 72n + 30n^2 + 32Cos[(n + 1)Pi/3] - (-1)^n)/24, {n, 0, 40}] (* Greg Dresden, Jun 22 2021 *)

Crossrefs

Sequence in context: A008050 A008039 A024986 * A140229 A100440 A027373

Adjacent sequences: A028355 A028356 A028357 * A028359 A028360 A028361

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved