A087099 Partial sums of A063914.

1, 3, 6, 11, 16, 24, 31, 42, 51, 65, 76, 93, 106, 126, 141, 164, 181, 207, 226, 255, 276, 308, 331, 366, 391, 429, 456, 497, 526, 570, 601, 648, 681, 731, 766, 819, 856, 912, 951, 1010, 1051, 1113, 1156, 1221, 1266, 1334, 1381, 1452, 1501, 1575, 1626

Offset: 1

Author

Jeremy Gardiner, Aug 10 2003

Keywords

• easy
• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 1..1000
• Index entries for linear recurrences with constant coefficients, signature (0,2,0,-1).

Crossrefs

Cf. A086848, A087098, A001068.

Programs

Mathematica

With[{nn=50},Accumulate[Riffle[Range[1,2*nn,2],3*Range[0,nn]+2]]] (* Harvey P. Dale, Jul 25 2013 *)

Formula

From Chai Wah Wu, Feb 02 2021: (Start)

a(n) = 2*a(n-2) - a(n-4) for n > 4.

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