A038716 a(n) = floor(n/4)*ceiling((n+3)/4).

0, 0, 0, 0, 2, 2, 3, 3, 6, 6, 8, 8, 12, 12, 15, 15, 20, 20, 24, 24, 30, 30, 35, 35, 42, 42, 48, 48, 56, 56, 63, 63, 72, 72, 80, 80, 90, 90, 99, 99, 110, 110, 120, 120, 132, 132, 143, 143, 156, 156, 168, 168, 182, 182, 195, 195, 210, 210, 224, 224, 240

Offset

0,5

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..10000

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

Formula

a(n) = a(n-1) + a(n-2) - a(n-3) + a(n-4) - a(n-5) - a(n-6) + a(n-7). - R. J. Mathar, Mar 11 2012

G.f.: x^4*(2 - x^2)/((-1-x^2)*(-1+x)^3*(1+x)^2). - Elmo R. Oliveira, May 05 2026

Maple

A038716:=n->floor(n/4)*ceil((n+3)/4): seq(A038716(n), n=0..100); # Wesley Ivan Hurt, Jan 03 2017

Mathematica

Table[Floor[n/4]Ceiling[(n+3)/4], {n, 0, 70}] (* Harvey P. Dale, Sep 19 2011 *)

Prog

(Magma) [Floor(n/4)*Ceiling((n+3)/4): n in [0..60]]; // Vincenzo Librandi, Sep 21 2011

Crossrefs

Cf. A038715.

Sequence in context: A147795 A258186 A357415 * A168659 A035642 A213332

Adjacent sequences: A038713 A038714 A038715 * A038717 A038718 A038719

Keyword

nonn,easy

Author

N. J. A. Sloane, May 02 2000

Status

approved