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 A219637 #7 Nov 25 2012 23:46:23 %S A219637 0,2,4,7,9,12,14,16,20,22,24,27,29,33,35,37,40,42,45,47,49,54,56,58, %T A219637 61,63,66,68,70,74,76,78,81,83,88,90,92,95,97,100,102,104,108,110,112, %U A219637 115,117,121,123,125,128,130,133,135,137,143,145,147,150,152,155 %N A219637 Numbers that occur twice in A219641. %H A219637 A. Karttunen, <a href="/A219637/b219637.txt">Table of n, a(n) for n = 1..10000</a> %o A219637 (Scheme with _Antti Karttunen_'s Intseq-library): %o A219637 (define (Aux_for219637 n) (A219641 (A219636 n))) %o A219637 (define A219637 (DISTINCT-VALS 1 1 Aux_for219637)) %Y A219637 Cf. A219636, A219639, A219641. %K A219637 nonn %O A219637 1,2 %A A219637 _Antti Karttunen_, Nov 24 2012