# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a336898 Showing 1-1 of 1 %I A336898 #9 Aug 28 2020 10:16:18 %S A336898 1,1,1,3,1,5,1,7,1,9,5,11,1,13,7,15,1,17,1,19,1,3,11,23,1,25,13,27,7, %T A336898 29,5,31,1,33,17,35,1,37,19,39,1,41,1,43,11,45,23,47,1,49,25,51,13,53, %U A336898 1,55,7,57,29,59,1,61,31,9,1,65,11,67,17,69,35,71,1,73 %N A336898 a(n) = numerator(n / (4^n - 2^n)) for n > 0 and a(0) = 1. %e A336898 r(n) = 1, 1/2, 1/6, 3/56, 1/60, 5/992, 1/672, 7/16256, 1/8160, 9/261632, ... %p A336898 r := n -> `if`(n=0, 1, n/(4^n - 2^n)): seq(numer(r(n)), n=0..72); %o A336898 (PARI) a(n) = if (n==0, 1, numerator(n / (4^n - 2^n))); \\ _Michel Marcus_, Aug 28 2020 %Y A336898 Cf. A336899 (denominator). %K A336898 nonn,frac %O A336898 0,4 %A A336898 _Peter Luschny_, Aug 28 2020 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE