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 A219644 #7 Nov 25 2012 23:49:09 %S A219644 1,1,1,2,2,1,2,3,2,3,3,2,3,3,3,2,2,3,3,3,2,3,4,1,2,3,3,3,2,3,4,3,3,3, %T A219644 5,2,3,3,3,2,3,4,3,3,3,5,3,4,4,4,5,1,2,3,3,3,2,3,4,3,3,3,5,3,4,4,4,5, %U A219644 3,3,3,5,5,3,5,5,3,2,3,3,3,2,3,4,3,3,3 %N A219644 Run lengths in A219642. %C A219644 a(n) tells from how many starting values one can end to 0 in n steps, with the iterative process described in A219642 (if going around in 0->0 loop is disallowed). %H A219644 A. Karttunen, <a href="/A219644/b219644.txt">Table of n, a(n) for n = 0..10000</a> %F A219644 a(n) = A219643(n+1)-A219643(n). (The first differences of A219643). %o A219644 (Scheme, with two different variants): %o A219644 (define (A219644 n) (- (A219643 (1+ n)) (A219643 n))) %o A219644 (define (A219644v2 n) (1+ (- (A219645 n) (A219643 n)))) %Y A219644 a(n) = 1+(A219645(n)-A219643(n)). %Y A219644 This sequence is based on Fibonacci number system (Zeckendorf expansion): A014417. Analogous sequence for binary system: A086876, for factorial number system: A219654. %K A219644 nonn %O A219644 0,4 %A A219644 _Antti Karttunen_, Nov 24 2012