A277675 - OEIS

%I #17 Aug 21 2022 19:37:36

%S 1,3,7,11,15,19,24,28,33,38,43,48,54,59,64,70,75,81,87,93,98,104,110,

%T 116,122,128,135,141,147,153,159,166,172,179,185,192,198,205,211,218,

%U 224,231,238,244,251,258,265,271,278,285,292,299,306,313,320,327

%N 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!.

%C Positions of 0 in A277674.

%H Clark Kimberling, <a href="/A277675/b277675.txt">Table of n, a(n) for n = 1..1000</a>

%e (See A277674.)

%t d = Differences@Array[Floor@Log[#, #!] &, 10000, 2]; (* _Robert G. Wilson v_, Oct 27 2016 *)

%t u = Flatten[Position[d, 0]]; (* A277675 *)

%t v = Flatten[Position[d, 1]]; (* A277676 *)

%t SequencePosition[Table[IntegerLength[n!,n],{n,2,350}],{x_,x_}][[All,1]] (* _Harvey P. Dale_, Aug 21 2022 *)

%o (PARI) d(n) = #digits(n!, n);

%o isok(n) = d(n+2) == d(n+1); \\ _Michel Marcus_, Oct 29 2016

%Y Cf. A000142, A060151, A277674, A277676.

%K nonn,base,easy

%O 1,2

%A _Clark Kimberling_, Oct 26 2016