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%I #9 Apr 21 2021 12:59:55
%S 4,9,16,23,30,38,46,53,61,69,77,85,93,101,109,117,124,132,140,148,156,
%T 164,172,180,188,196,204,212,220,228,236,244,252,260,268,276,284,292,
%U 300,308,316,324,332,340,348,356,364,372,380,388
%N a(n) = floor( 2*(1 + n + 2*n^2 + 4*n^3)/(1 + 2*n + n^2)).
%e 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.
%t Table[Floor[(2(1+n+2n^2+4n^3))/(1+2n+n^2)],{n,50}] (* _Harvey P. Dale_, Apr 01 2018 *)
%o (PARI) a(n) = floor(2*((1 + n + 2*n^2 + 4*n^3)/(1 + 2*n + n^2))); \\ _Michel Marcus_, Aug 31 2013
%Y Cf. A086790, A086814, A086822.
%K nonn,easy
%O 1,1
%A Wang Dan (wangdan01(AT)lycos.com), Aug 15 2003
%E Definition corrected by _Michel Marcus_, Aug 31 2013