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 A187486 #6 Mar 30 2012 17:26:37 %S A187486 0,15,0,25,0,35,0,45,0,55,0,65,0,75,0,85,15,95,0,105,0,115,0,125,0, %T A187486 135,0,145,25,155,0,165,0,175,0,185,0,195,0,205,35,215,0,225,0,235,0, %U A187486 245,0,255,0,265,45,275,0,285,0,295,0,305,0,315,0,325,55,335,0,345,0,355 %N A187486 Distance between first and second positions of A181762(n). %C A187486 Some entries of A181762 occur twice some only once. %C A187486 The sequence gives the distance between first and second positions of A181762(n), %C A187486 a(n)=0 if A181762(n) occurs only once. %C A187486 The numbers that occur in A181762 only once are 0, 2, 4, 6, 8, 10, 12, 14, 18, 20, 22, 24, 26, 30, 32, 34, 36, 38, 42, 44, 46, ... %Y A187486 Cf. A181762. %K A187486 nonn %O A187486 0,2 %A A187486 _Zak Seidov_, Mar 10 2011