%I #9 Jan 20 2017 20:33:58
%S 4,4,5,8,12,21,36,64,113,204,372,682,1260,2340,4369,8192,15420,29127,
%T 55188,104857,199728,381300,729444,1398101,2684354,5162220,9942053,
%U 19173961,37025580,71582788,138547332,268435456,520602096,1010580540,1963413621,3817748707,7429132620,14467258260,28192605840,54975581388
%N a(n) = floor(2^(n+1)/n).
%H Robert Israel, <a href="/A281375/b281375.txt">Table of n, a(n) for n = 1..3329</a>
%F a(n) = A053639(n) if n is in A000079, otherwise A053639(n)-1.
%F a(2k-1) = A191636(k) for k > 1.
%F a(n) = (2^(n+1)-A112983(n))/n.
%p seq(floor(2^(n+1)/n), n=1..50); # _Robert Israel_, Jan 20 2017
%o (PARI) a(n) = 2^(n+1)\n \\ _Felix Fröhlich_, Jan 20 2017
%Y Cf. A053639, A112983, A191636.
%K nonn,easy
%O 1,1
%A _Robert Israel_, Jan 20 2017