OFFSET
1,2
COMMENTS
There is no reason to allow permutations that begin with 0, because we can always gain a power of 2 by putting that zero at the other end. - N. J. A. Sloane, Apr 23 2016
LINKS
David A. Corneth, Table of n, a(n) for n = 1..10000
EXAMPLE
The numbers obtained by permuting the digits of 1336 are 1336, 1363, 1633, 3136, 3163, 6133, 3316, 3613, 6313, 3361, 3631 and 6331. The highest power of 2 dividing any of these is 2^6, which divides just one of them, 3136, so a(1336) = 3136.
MATHEMATICA
hp2[n_]:=Module[{c={#, IntegerExponent[#, 2]}&/@(FromDigits/@ Permutations[ IntegerDigits[ n]]), mx}, mx=Max[c[[All, 2]]]; Min[Select[c, #[[2]]==mx&][[All, 1]]]]; Array[hp2, 90] (* Harvey P. Dale, Jan 27 2020 *)
CROSSREFS
KEYWORD
AUTHOR
David A. Corneth, Apr 22 2016
STATUS
approved