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

Offset

1,3

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. *)

Example

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

Mathematica

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

Crossrefs

Cf. A213857.

Sequence in context: A347655 A056177 A025199 * A277992 A180968 A191847

Adjacent sequences: A213855 A213856 A213857 * A213859 A213860 A213861

Keyword

nonn,easy

Author

Clark Kimberling, Jul 17 2012

Extensions

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

Status

approved