cp's OEIS Frontend

A213855 Least m > 0 such that m! * 4^m >= n!.

%I A213855 #13 Jun 13 2021 03:21:12
%S A213855 1,1,2,2,3,4,4,5,6,7,7,8,9,9,10,11,12,12,13,14,15,15,16,17,18,18,19,
%T A213855 20,21,22,22,23,24,25,25,26,27,28,28,29,30,31,32,32,33,34,35,36,36,37,
%U A213855 38,39,39,40,41,42,43,43,44,45,46,47,47,48
%N A213855 Least m > 0 such that m! * 4^m >= n!.
%H A213855 Clark Kimberling, <a href="/A213855/b213855.txt">Table of n, a(n) for n = 1..1000</a>
%e A213855 a(5) = 3 because (4^2)*2! < 5! <= (4^3)*3!.
%p A213855 A213855 := proc(n)
%p A213855         for m from 1 do
%p A213855                 if (4^m)*m! >= n! then
%p A213855                         return m;
%p A213855                 end if;
%p A213855         end do:
%p A213855 end proc: # _R. J. Mathar_, Jul 18 2012
%t A213855 Table[m=1; While[n!>(4^m)*m!, m++]; m, {n,1,100}]
%Y A213855 Cf. A213854.
%K A213855 nonn,easy
%O A213855 1,3
%A A213855 _Clark Kimberling_, Jul 17 2012