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 A138298 #4 Mar 30 2012 18:51:57 %S A138298 0,2,10,21,110,233,1220,2584,13530,28657,150050,317811,1664080, %T A138298 3524578,18454930,39088169,204668310,433494437,2269806340,4807526976, %U A138298 25172538050,53316291173,279167724890,591286729879,3096017511840 %N A138298 First differences of A137976 after having added two leading ones. %F A138298 a(n)= A137986(n)-A137986(n-1), n>=2. %F A138298 a(2n)= 2*A102312(n)= 10*A049666(n). a(2n+1)= A134490(n). %K A138298 nonn %O A138298 0,2 %A A138298 _Paul Curtz_, May 07 2008 %E A138298 Edited and extended by _R. J. Mathar_, Jul 28 2008