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 A259656 #23 Nov 05 2015 12:22:13 %S A259656 1,2,1,2,1,2,1,2,1,2,3,2,3,2,1,2,1,2,3,2,1,2,3,2,3,2,1,2,3,2,1,2,1,2, %T A259656 3,2,3,4,3,4,3,2,3,2,1,2,3,2,3,2,1,4,3,2,3,4,3,4,3,2,3,2,1,2,1,2,3,2, %U A259656 3,2,3,2,1,2,3,2,3,2,3,4,3,2,3 %N A259656 Let f(x) be the absolute value of the difference between x and its base-2 reversal. a(n) is the number of times f(x) must be applied starting with n for the result to be 0. %C A259656 First differences appear to always be odd. %C A259656 More precisely, a(n) is even if n is even and a(n) is odd when n is odd. This is an immediate consequence of the parities in A055945 (which represents f apart from the sign) and the fact that we count iterations of f until the result is even. - _Jörgen Backelin_, Nov 04 2015 %p A259656 A259656 := proc(n) %p A259656 local f,a ; %p A259656 f := n ; %p A259656 a := 0 ; %p A259656 while f <> 0 do %p A259656 f := abs(A055945(f)) ; %p A259656 a := a+1 ; %p A259656 end do: %p A259656 a; %p A259656 end proc: # _R. J. Mathar_, Nov 04 2015 %Y A259656 Cf. A055945. %K A259656 nonn,base %O A259656 1,2 %A A259656 _Dylan Hamilton_, Jul 02 2015