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 A227944 #27 Oct 11 2016 15:40:50 %S A227944 0,1,1,1,1,1,2,1,2,1,2,1,2,2,1,1,1,2,3,1,2,2,3,1,2,2,3,2,3,1,2,1,2,1, %T A227944 2,2,3,3,2,1,2,2,3,2,2,3,4,1,3,2,1,2,3,3,2,2,3,3,4,1,2,2,3,1,2,2,3,1, %U A227944 3,2,3,2,3,3,2,3,2,2,3,1,4,2,3,2,1,3,3,2,3,2,3,3,2,4,3,1,2,3,2,2 %N A227944 Number of iterations of "take odd part of phi" (A053575) to reach 1 from n. %C A227944 a(n) >= A256757(n) - 1. %H A227944 T. D. Noe, <a href="/A227944/b227944.txt">Table of n, a(n) for n = 1..10000</a> %F A227944 For n > 1, a(n) = a(A053575(n)) + 1. %e A227944 a(18) = 2 because it takes two steps to reach 1 from 18: phi(18) = 6, the odd part of which is 3, and phi(3) = 2, the odd part of which is 1. %e A227944 a(19) = 3 because it takes three steps to reach 1 from 19: phi(19) = 18, the odd part of which is 9, and phi(9) = 6, the odd part of which is 3, and phi(3) = 2, the odd part of which is 1. %t A227944 oddPhi[n_] := Module[{phi = EulerPhi[n]}, phi/2^IntegerExponent[phi, 2]]; Table[Length[NestWhileList[oddPhi[#] &, n, # > 1 &]] - 1, {n, 100}] (* _T. D. Noe_, Oct 07 2013 *) %o A227944 (Haskell) %o A227944 a227944 n = fst $ %o A227944 until ((== 1) . snd) (\(i, x) -> (i + 1, a053575 x)) (0, n) %o A227944 -- _Reinhard Zumkeller_, Oct 09 2013 %Y A227944 A variant of A049115: a(n) = A049115(n) unless n is a power of 2. %Y A227944 Cf. A003434, A227946. %K A227944 nonn,easy %O A227944 1,7 %A A227944 _Max Alekseyev_, Oct 03 2013