%N Positions at which powers of 2 occur in A051145.
%C A209229(A051145(a(n))) = 1;
%C the definition of this sequence was the original definition of A051147.
%o import Data.List (findIndices)
%o a244747 n = a244747_list !! (n-1)
%o a244747_list = findIndices ((== 1) . a209229) a051145_list
%Y Cf. A209229, A051147 (subsequence).
%A _Reinhard Zumkeller_, Jul 05 2014