This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A300726 #12 Mar 24 2018 18:54:50 %S A300726 0,1,1,2,1,3,1,4,2,5,1,6,1,5,5,8,1,10,1,10,5,9,1,12,4,9,8,10,1,13,1, %T A300726 16,9,17,7,20,1,17,9,20,1,21,1,18,14,17,1,24,4,20,17,18,1,24,11,20,17, %U A300726 17,1,26,1,17,22,32,11,41,1,34,17,39,1,40,1,33,20,34,11,41,1,40,16,33,1,42,19,33,17,36,1,46,11,34,17,33,19 %N A300726 Difference between A053644 (the largest power of 2 less than or equal to n) and its Möbius transform. %H A300726 Antti Karttunen, <a href="/A300726/b300726.txt">Table of n, a(n) for n = 1..65537</a> %F A300726 a(n) = -Sum_{d|n, d<n} A008683(n/d)*A053644(d). %F A300726 a(n) = A053644(n) - A300724(n). %t A300726 With[{s = Array[2^Floor@ Log2@ # &, 95]}, Table[s[[n]] - DivisorSum[n, MoebiusMu[n/#] s[[#]] &], {n, Length@ s}]] (* _Michael De Vlieger_, Mar 13 2018 *) %o A300726 (PARI) %o A300726 A053644(n) = { my(k=1); while(k<=n, k<<=1); (k>>1); }; \\ From A053644 %o A300726 A300726(n) = -sumdiv(n,d,(d<n)*moebius(n/d)*A053644(d)); %Y A300726 Cf. A008683, A053644, A300724, A300725, A300244. %K A300726 nonn,look %O A300726 1,4 %A A300726 _Antti Karttunen_, Mar 11 2018