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 A191637 a(n) = floor((1 + 4^n)/(1 + 2*n)). 2

%I

%S 1,3,9,28,93,315,1092,3855,13797,49932,182361,671088,2485513,9256395,

%T 34636833,130150524,490853405,1857283155,7048151460,26817356775,

%U 102280151421,390937467653,1497207322929,5744387279809,22076468761620,84973577874915,327534518354217

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

%H Vincenzo Librandi, <a href="/A191637/b191637.txt">Table of n, a(n) for n = 1..1000</a>

%t f[n_] := Floor[(1+4^n)/(1+2 n)]

%t Table[f[n], {n, 1, 40}] (* A191637 *)

%o (MAGMA) [Floor((1+4^n)/(1+2*n)): n in [1..30] ]; // _Vincenzo Librandi_, Sep 10 2011

%o (Maxima) A191637(n):=floor((1+4^n)/(1+2*n))\$ makelist(A191637(n),n,1,30); /* _Martin Ettl_, Oct 25 2012 */

%Y Cf. A191636.

%K nonn

%O 1,2

%A _Clark Kimberling_, Jun 09 2011

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Last modified February 27 21:57 EST 2020. Contains 332311 sequences. (Running on oeis4.)