A085899 a(n) = floor( 2*(1 + n + 2*n^2 + 4*n^3)/(1 + 2*n + n^2)).

4, 9, 16, 23, 30, 38, 46, 53, 61, 69, 77, 85, 93, 101, 109, 117, 124, 132, 140, 148, 156, 164, 172, 180, 188, 196, 204, 212, 220, 228, 236, 244, 252, 260, 268, 276, 284, 292, 300, 308, 316, 324, 332, 340, 348, 356, 364, 372, 380, 388

Offset: 1

Author

Wang Dan (wangdan01(AT)lycos.com), Aug 15 2003

Keywords

• nonn
• easy

Examples

			a(2) = floor(2*(1*2^0+1*2^1+2*2^2+4*2^3)/(1*2^0+2*2^1+1*2^2)) = floor(2*43/9) = floor(9.55556) = 9.
		

Crossrefs

Cf. A086790, A086814, A086822.

Programs

Mathematica

Table[Floor[(2(1+n+2n^2+4n^3))/(1+2n+n^2)],{n,50}] (* Harvey P. Dale, Apr 01 2018 *)

PARI

a(n) = floor(2*((1 + n + 2*n^2 + 4*n^3)/(1 + 2*n + n^2))); \\ Michel Marcus, Aug 31 2013

Extensions

Definition corrected by Michel Marcus, Aug 31 2013