A036404 a(n) = ceiling(n^2/5).

0, 1, 1, 2, 4, 5, 8, 10, 13, 17, 20, 25, 29, 34, 40, 45, 52, 58, 65, 73, 80, 89, 97, 106, 116, 125, 136, 146, 157, 169, 180, 193, 205, 218, 232, 245, 260, 274, 289, 305, 320, 337, 353, 370, 388, 405, 424, 442, 461, 481, 500, 521, 541, 562, 584

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Links

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

Formula

G.f. -x*(1+x)*(x^2-x+1)^2 / ( (x^4+x^3+x^2+x+1)*(x-1)^3 ). - R. J. Mathar, Jan 22 2011