%I #14 Oct 16 2019 03:34:36
%S 1,4,16,64,256,1024,4096,16384,1048576,4194304,268435456,1073741824,
%T 4294967296,17179869184,68719476736,281474976710656,18014398509481984,
%U 72057594037927936,73786976294838206464,295147905179352825856,1208925819614629174706176,20282409603651670423947251286016,85070591730234615865843651857942052864
%N Numbers of form 4^k (values of k see A050725) containing no pair of consecutive equal digits (probably finite).
%C No additional terms up to 4^25000. - _Harvey P. Dale_, Oct 06 2011
%t Select[4^Range[0,60],!MemberQ[Differences[IntegerDigits[#]],0]&] (* _Harvey P. Dale_, Oct 06 2011 *)
%Y Cf. A043096, A050725.
%K nonn,base
%O 1,2
%A _Patrick De Geest_, Sep 15 1999
%E Terms a(21), a(22), and a(23) added by _Harvey P. Dale_, Oct 06 2011