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 A141748 #3 Mar 30 2012 18:57:10 %S A141748 2,3,4,7,9,10,13,19,25,28,29,31,33,41,43,59,65,67,73,82,83,85,89,91, %T A141748 97,113,129,131,137,145,155,209,244,245,247,251,257,265,275,283,307, %U A141748 337,371,499,513,515,521,539,593,730,731,733,737,745,755,761,793,857,985 %N A141748 a(n) = n-th nonnegative integer k such that there is a unique nonnegative integer pair (i,j) for which n = 2^i + 3^j. %C A141748 Locations of 1's in A141747. %Y A141748 Cf. A141747, A085634. %K A141748 nonn %O A141748 1,1 %A A141748 _Clark Kimberling_, Jul 01 2008