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 A220969 #6 Jul 13 2013 12:04:36 %S A220969 2,3,4,7,8,10,12,14,18,19,22,24,26,30,32,35,37,41,43,46,48,51,53,57, %T A220969 59,62,64,66,69,72,78,80,83,84,88,91,95,99,102,103,107,109,110,115, %U A220969 116,117,120,122,129,133,137,138,139,140,144,146,152,154,156,160 %N A220969 Positions in A030229 where even terms occur. %C A220969 A030229(a(n)) mod 2 = 0; A020639(A030229(a(n))) = 2. %H A220969 Reinhard Zumkeller, <a href="/A220969/b220969.txt">Table of n, a(n) for n = 1..10000</a> %o A220969 (Haskell) %o A220969 import Data.List (findIndices) %o A220969 a220969 n = a220969_list !! (n-1) %o A220969 a220969_list = map (+ 1) $ findIndices even a030229_list %Y A220969 Cf. A220968 (complement). %K A220969 nonn %O A220969 1,1 %A A220969 _Reinhard Zumkeller_, Dec 27 2012