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

1,2

Comments

Positions of 0 in A277674.

Links

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

Example

(See A277674.)

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 *)

Prog

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

Crossrefs

Cf. A000142, A060151, A277674, A277676.

Sequence in context: A079422 A310210 A292657 * A220496 A194442 A220522

Adjacent sequences: A277672 A277673 A277674 * A277676 A277677 A277678

Keyword

nonn,base,easy

Author

Clark Kimberling, Oct 26 2016

Status

approved