OFFSET
1,1
COMMENTS
If there is a term beyond a(747) = 7954, it is larger than 250000. - Giovanni Resta, Oct 14 2019
LINKS
Giovanni Resta, Table of n, a(n) for n = 1..747
EXAMPLE
2^26 = 671088{64};
2^31 = 2147483{64}8;
2^46 = 703687441776{64}.
MATHEMATICA
sub2[n_] := Block[{s = ToString[2^n], k = n - 1}, While[k >= 0 && ! StringContainsQ[s, ToString[2^k]], k--]; k]; Select[Range[300], sub2[#] == 6 &] (* Giovanni Resta, Oct 14 2019 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, Jun 15 1998
STATUS
approved