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 A091871 #6 Jul 18 2014 14:30:27 %S A091871 2,4,5,6,7,8,11,12,20,21,22,25,30,32,33,34,40,41,43,44,45,46,64,65,66, %T A091871 67,68,74,75,78,128,130,131,137,139,156,157,159,164,165,167,168,187, %U A091871 193,196,215,220,222,270,275,293,294,295,298,299,301,302,303,444,446 %N A091871 A091633 indexed by A000040. %H A091871 Reinhard Zumkeller, <a href="/A091871/b091871.txt">Table of n, a(n) for n = 1..10000</a> %F A091871 a(n)=k such that A000040(k) = A091633(n). %F A091871 a(n) = A049084(A091633(n)). - _Reinhard Zumkeller_, Jul 18 2014 %o A091871 (Haskell) %o A091871 a091871 n = a091871_list !! (n-1) %o A091871 a091871_list = f [1..] a000040_list where %o A091871 f (i:is) (p:ps) = if (null $ show p `intersect` "024568") %o A091871 then i : f is ps else f is ps %o A091871 -- _Reinhard Zumkeller_, Jul 18 2014 %Y A091871 Cf. A049084, A091633, A136333. %K A091871 easy,nonn,base %O A091871 1,1 %A A091871 _Ray Chandler_, Feb 07 2004