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 A048728 #18 Jun 14 2017 07:14:51 %S A048728 0,0,0,4,0,0,8,12,0,0,0,4,16,16,24,28,0,0,0,4,0,0,8,12,32,32,32,36,48, %T A048728 48,56,60,0,0,0,4,0,0,8,12,0,0,0,4,16,16,24,28,64,64,64,68,64,64,72, %U A048728 76,96,96,96,100,112,112,120 %N A048728 Differences between A008585 (multiples of 3) and A048724. %H A048728 Reinhard Zumkeller, <a href="/A048728/b048728.txt">Table of n, a(n) for n = 0..10000</a> %F A048728 a(n) = n*3 - Xmult(n, 3). %o A048728 (Haskell) %o A048728 a048728 n = a008585 n - a048724 n -- _Reinhard Zumkeller_, May 13 2014 %o A048728 (PARI) a(n)=3*n - bitxor(2*n, n) \\ _Charles R Greathouse IV_, Oct 03 2016 %o A048728 (Python) %o A048728 def a(n): return 3*n - (2*n^n) # _Indranil Ghosh_, Jun 13 2017 %Y A048728 Positions of zeros are given by A003714. Cf. A048735, A242400. %Y A048728 Diagonal 3 of A061858. %K A048728 nonn,easy %O A048728 0,4 %A A048728 _Antti Karttunen_, Apr 26 1999