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 A230431 #5 Oct 30 2013 11:52:17 %S A230431 0,0,0,1,0,1,2,3,4,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,0,1, %T A230431 2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26, %U A230431 27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44 %N A230431 After the first zero, integers from 0 to A219661(n)-1 followed by integers from 0 to A219661(n+1)-1, etc. %F A230431 a(0) = a(1) = 0, and for n > 1, a(n) = n - A219665(A230411(n+1)-1). %o A230431 (Scheme) %o A230431 (define (A230431 n) (if (< n 2) 0 (- n (A219665 (-1+ (A230411 (+ n 1))))))) %Y A230431 Cf. A219661, A219665, A230411. Used to compute A230432. %Y A230431 Analogous sequence for binary system: A218601. %K A230431 nonn %O A230431 0,7 %A A230431 _Antti Karttunen_, Oct 22 2013