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 A116648 #2 Mar 31 2012 13:21:11 %S A116648 2,2,4,4,5,5,5,5,7,7,7,7,7,7,9,9,11,11,11,11,11,11,18,18,19,19,19,19, %T A116648 20,20,20,20,21,21,21,21,21,21,21,21,27,27,27,27,27,27,27,27,29,29,29, %U A116648 29,30,30,30,30,30,30,30,30,30,30,39,39,39,39,42,42,42,42,44,44,44,44 %N A116648 Least natural number which does not occur in A116626(1..n). %o A116648 (MIT Scheme:) (define (A116648 n) (if (< n 2) (+ n 1) (let ((prev (A116648 (- n 1)))) (cond ((not (= (A116626 n) prev)) prev) (else (let loop ((i (+ 1 prev))) (cond ((> (A116627 i) n) i) (else (loop (+ 1 i)))))))))) %Y A116648 Cf. A116649, A116650, A116651. %K A116648 nonn %O A116648 1,1 %A A116648 _Antti Karttunen_, Feb 21 2006