A008238 a(n) = floor(n/4)*ceiling(n/4).

0, 0, 0, 0, 1, 2, 2, 2, 4, 6, 6, 6, 9, 12, 12, 12, 16, 20, 20, 20, 25, 30, 30, 30, 36, 42, 42, 42, 49, 56, 56, 56, 64, 72, 72, 72, 81, 90, 90, 90, 100, 110, 110, 110, 121, 132, 132, 132, 144, 156, 156, 156, 169, 182, 182

Offset

0,6

Links

Table of n, a(n) for n=0..54.

Index entries for linear recurrences with constant coefficients, signature (2,-2,2,0,-2,2,-2,1).

Formula

G.f.: x^4/((1-x)^3*(1+x)*(1+x^2)^2). - R. J. Mathar, Mar 11 2012

a(n) = floor(n/4)*floor((n+3)/4). - Bruno Berselli, Jun 08 2017

Mathematica

f[n_]:=Module[{c=n/4}, Floor[c]Ceiling[c]]; f/@Range[0, 70]  (* Harvey P. Dale, Apr 23 2011 *)

Crossrefs

Cf. A002265.

Sequence in context: A170887 A103265 A341695 * A218870 A264869 A292728

Adjacent sequences: A008235 A008236 A008237 * A008239 A008240 A008241

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved