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 A262677 #5 Oct 03 2015 08:44:20 %S A262677 0,1,0,2,1,3,0,4,1,1,0,2,0,3,0,3,2,4,0,5,0,5,0,6,2,1,0,7,0,8,0,9,0,9, %T A262677 0,10,7,11,0,11,0,12,0,13,0,12,0,13,0,1,0,14,0,15,0,15,0,16,0,17,0,18, %U A262677 0,17,16,19,0,20,0,20,0,21,0,22,0,21,0,23,0,24,0,1,0,2,0,2,0,3,0,4,0,4,0,5,0,5,0,6,0,6,4,7,0,8,0,7,0,8 %N A262677 Number of odd numbers encountered when iterating A049820 starting from n: a(0) = 0 and for n >= 1, a(n) = A000035(n) + a(A049820(n)). %C A262677 Number of odd numbers encountered before zero is reached when starting from k = n and repeatedly applying the map that replaces k by k - d(k), where d(k) is the number of divisors of k (A000005). This count includes n itself if it is odd. %H A262677 Antti Karttunen, <a href="/A262677/b262677.txt">Table of n, a(n) for n = 0..10080</a> %F A262677 a(0) = 0; for n >= 1, a(n) = A000035(n) + a(A049820(n)). %F A262677 Other identities. For all n >= 0: %F A262677 A155043(n) = A262676(n) + a(n). %o A262677 (Scheme, with memoization-macro definec) %o A262677 (definec (A262677 n) (if (zero? n) n (+ (A000035 n) (A262677 (A049820 n))))) %Y A262677 Cf. A000005, A000035, A049820, A155043, A262676, A262680. %K A262677 nonn %O A262677 0,4 %A A262677 _Antti Karttunen_, Oct 03 2015