A213858 Least m such that n! <= 4^m.

0, 1, 2, 3, 4, 5, 7, 8, 10, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 38, 40, 42, 45, 47, 49, 52, 54, 57, 59, 62, 64, 67, 70, 72, 75, 77, 80, 83, 85, 88, 91, 94, 96, 99, 102, 105, 108, 110, 113, 116, 119, 122, 125, 128, 131, 134, 137, 140, 143, 145, 148

Offset: 1

Author

Clark Kimberling, Jul 17 2012

Keywords

• nonn
• easy

Examples

			a(11) = 13 because 4^12 < 11! <= 4^13.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000 (Identical to file previously submitted by Clark Kimberling except for first term.)

Crossrefs

Cf. A213857.

Programs

Mathematica

Ceiling[Log[4,Range[100]!]] (* Harvey P. Dale, Jul 21 2016 *)

Extensions

Corrected (a(1) changed to zero) by Harvey P. Dale, Jul 21 2016