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 A277011 #8 Sep 26 2016 20:46:54 %S A277011 0,1,2,2,6,3,4,3,24,7,8,4,12,5,6,4,120,25,26,8,30,9,10,5,48,13,14,6, %T A277011 18,7,8,5,720,121,122,26,126,27,28,9,144,31,32,10,36,11,12,6,240,49, %U A277011 50,14,54,15,16,7,72,19,20,8,24,9,10,6,5040,721,722,122,726,123,124,27,744,127,128,28,132,29,30,10,840,145,146,32 %N A277011 Left inverse of A277012. %H A277011 Antti Karttunen, <a href="/A277011/b277011.txt">Table of n, a(n) for n = 0..8191</a> %H A277011 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a> %H A277011 <a href="/index/Fa#facbase">Index entries for sequences related to factorial base representation</a> %F A277011 a(n) = A276075(A005940(1+n)). %F A277011 For all n >= 0, a(A277012(n)) = n. %o A277011 (Scheme) %o A277011 ;; Standalone iterative implementation: %o A277011 (define (A277011 n) (let loop ((s 0) (n n) (r 0) (i 2) (f 1)) (cond ((zero? n) (+ s (* r f))) ((even? n) (loop (+ s (* r f)) (/ n 2) 0 (+ 1 i) (* i f))) (else (loop s (/ (- n 1) 2) (+ 1 r) i f))))) %Y A277011 Left inverse of A277012. %Y A277011 Cf. A005940, A276075. %Y A277011 Cf. also A277007. %K A277011 nonn,base %O A277011 0,3 %A A277011 _Antti Karttunen_, Sep 25 2016