A086814 - OEIS

%I #10 Aug 11 2019 14:00:23

%S 2,5,9,12,16,20,24,27,31,35,39,43,47,51,55,59,63,67,71,75,79,83,87,91,

%T 95,99,103,107,111,115,119,123,127,131,135,139,143,147,151,155,159,

%U 163,167,171,175,179,183,187,191,195

%N a(n) = ceiling( (1 + n + 2*n^2 + 4*n^3)/(1 + 2*n + n^2) ).

%e a(2) = ceiling( (1*2^0 + 1*2^1 + 2*2^2 + 4*2^3)/(1*2^0 + 2*2^1 + 1*2^2) ) = ceiling(43/9) = ceiling(4.7777...) = 5.

%t Table[Ceiling[(1+n+2n^2+4n^3)/(1+2n+n^2)],{n,50}] (* _Harvey P. Dale_, Aug 11 2019 *)

%o (PARI) a(n) = ceil((1 + n + 2*n^2 + 4*n^3)/(1 + 2*n + n^2)); \\ _Michel Marcus_, Aug 31 2013

%Y Cf. A086790.

%K nonn,easy

%O 1,1

%A Wang Dan (wangdan01(AT)lycos.com), Aug 06 2003