A082644 a(n) = floor(n*(n-1/2)/2).

0, 0, 1, 3, 7, 11, 16, 22, 30, 38, 47, 57, 69, 81, 94, 108, 124, 140, 157, 175, 195, 215, 236, 258, 282, 306, 331, 357, 385, 413, 442, 472, 504, 536, 569, 603, 639, 675, 712, 750, 790, 830, 871, 913, 957, 1001, 1046, 1092, 1140, 1188, 1237, 1287, 1339, 1391, 1444, 1498

Offset

0,4

Links

Table of n, a(n) for n=0..55.

Formula

a(n) = floor(n^3/(2n+1)). - Gary Detlefs, Feb 11 2010

a(n) = (4*n!/(n-2)!+2*n-3+(-1)^n+(-1)^(n/2)-(-1)^((n+1)/2)+(-1)^(-n/2)-(-1)^(-(n+1)/2))/8. - Wesley Ivan Hurt, May 19 2016

Maple

seq(floor(n^3/(2*n+1)), n=0..25); # Gary Detlefs, Feb 11 2010

Mathematica

Table[Floor[n^3/(2 n + 1)], {n, 0, 60}] (* Wesley Ivan Hurt, May 19 2016 *)

Prog

(Magma) [Floor(n^3/(2*n+1)) : n in [0..60]]; // Wesley Ivan Hurt, May 19 2016

Crossrefs

Sequence in context: A022821 A001618 A118027 * A131024 A053982 A118000

Adjacent sequences: A082641 A082642 A082643 * A082645 A082646 A082647

Keyword

nonn,easy

Author

N. J. A. Sloane, May 16 2003

Status

approved