A129370 a(n)=n^2-(n-1)^2*(1-(-1)^n)/8.

0, 1, 4, 8, 16, 21, 36, 40, 64, 65, 100, 96, 144, 133, 196, 176, 256, 225, 324, 280, 400, 341, 484, 408, 576, 481, 676, 560, 784, 645, 900, 736, 1024, 833, 1156, 936, 1296, 1045, 1444, 1160, 1600, 1281, 1764, 1408

Offset

0,3

Comments

Partial sums are A129371.

Links

Table of n, a(n) for n=0..43.

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

Formula

G.f.: x(1+4x+5x^2+4x^3)/(1-x^2)^3; a(n)=((7n^2+2n-1)+(n-1)^2(-1)^n)/8;

Mathematica

Table[n^2-(n-1)^2 (1-(-1)^n)/8, {n, 0, 50}] (* Harvey P. Dale, Oct 22 2011 *)

Prog

(PARI) a(n)=n^2-(n-1)^2*(1-(-1)^n)/8 \\ Charles R Greathouse IV, Sep 28 2015

Crossrefs

Cf. A016742 (bisection), A000567 (bisection).

Sequence in context: A312807 A312808 A249486 * A344485 A212009 A312809

Adjacent sequences: A129367 A129368 A129369 * A129371 A129372 A129373

Keyword

easy,nonn

Author

Paul Barry, Apr 11 2007

Status

approved