# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a116416 Showing 1-1 of 1 %I A116416 #25 Aug 20 2017 10:54:56 %S A116416 0,1,1,3,1,4,5,11,1,5,3,7,7,19,13,25,1,6,7,17,8,23,31,61,9,29,19,39, %T A116416 47,107,77,137,1,7,2,5,1,3,1,2,5,17,11,23,3,7,5,9,11,41,13,28,7,17,6, %U A116416 11,37,97,67,127,19,39,29,49,1,8,9,23,10,31,41,83,11,39,25,53,61,145,103,187 %N A116416 If n = Sum_{m>=1} 2^(m-1) * b(n,m), where each b(n,m) is 0 or 1 and the sum is a finite sum, then a(n) = numerator of Sum_{m>=1} b(n,m)/m. %H A116416 Peter Kagey, Table of n, a(n) for n = 0..10000 %e A116416 13 in binary is 1101. So a(13) is the numerator of 1/4 + 1/3 + 1 = 19/12, since the binary digits at positions (from right to left) 1, 3 and 4 are each 1 and the other digits are 0. %t A116416 Table[Numerator@ Total@ MapIndexed[#1/ First@ #2 &, Reverse@ IntegerDigits[n, 2]], {n, 0, 79}] (* _Michael De Vlieger_, Aug 19 2017 *) %o A116416 (PARI) a(n) = {my(b = Vecrev(binary(n))); numerator(sum(k=1, #b, b[k]/k));} \\ _Michel Marcus_, Apr 18 2016 %Y A116416 Cf. A007088, A116417. %K A116416 easy,frac,nonn,look %O A116416 0,4 %A A116416 _Leroy Quet_, Feb 13 2006 %E A116416 More terms from _Joshua Zucker_, May 03 2006 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE