A277675 Numbers k such that d(k+2) = d(k+1), where d(m) is the number of digits in the base-m representation of m!.

1, 3, 7, 11, 15, 19, 24, 28, 33, 38, 43, 48, 54, 59, 64, 70, 75, 81, 87, 93, 98, 104, 110, 116, 122, 128, 135, 141, 147, 153, 159, 166, 172, 179, 185, 192, 198, 205, 211, 218, 224, 231, 238, 244, 251, 258, 265, 271, 278, 285, 292, 299, 306, 313, 320, 327

Offset: 1

Author

Clark Kimberling, Oct 26 2016

Keywords

• nonn
• base
• easy

Comments

Positions of 0 in A277674.

Examples

			(See A277674.)
		

Links

• Clark Kimberling, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000142, A060151, A277674, A277676.

Programs

Mathematica

d = Differences@Array[Floor@Log[#, #!] &, 10000, 2]; (* Robert G. Wilson v, Oct 27 2016 *)
u = Flatten[Position[d, 0]]; (* A277675 *)
v = Flatten[Position[d, 1]]; (* A277676 *)
SequencePosition[Table[IntegerLength[n!,n],{n,2,350}],{x_,x_}][[All,1]] (* Harvey P. Dale, Aug 21 2022 *)

PARI

d(n) = #digits(n!, n);
isok(n) = d(n+2) == d(n+1); \\ Michel Marcus, Oct 29 2016