A025646 - OEIS

%I #13 Jul 19 2021 03:38:06

%S 0,1,0,2,1,0,3,2,1,0,4,3,2,1,0,5,4,3,2,1,0,6,5,4,3,2,1,0,7,6,5,4,3,2,

%T 1,8,0,7,6,5,4,3,2,9,1,8,0,7,6,5,4,3,10,2,9,1,8,0,7,6,5,4,11,3,10,2,9,

%U 1,8,0,7,6,5,12,4,11,3,10,2,9,1,8,0,7,6,13,5,12,4,11,3,10,2,9,1,8,0,7,14,6,13

%N Exponent of 4 (value of i) in n-th number of form 4^i*5^j.

%H <a href="/index/Se#sequences_which_agree_for_a_long_time">Index entries for sequences which agree for a long time but are different</a>

%t With[{nn=15},IntegerExponent[#,4]&/@Union[Flatten[Table[4^x 5^y,{x,0,nn},{y,0,nn}]]]] (* _Harvey P. Dale_, May 10 2019 *)

%Y Cf. A025617.

%Y Differs from A025661 at a(1881).

%K nonn

%O 1,4

%A _David W. Wilson_