A136763 - OEIS

%I #17 Jan 15 2021 16:30:43

%S 1,1,2,6,1,9,4,2,1,12,9,8,7,7,8,9,11,1,1,2,3,5,9,1,2,4,9,1,3,7,1,3,7,

%T 1,3,10,2,6,1,4,1,3,10,2,9,2,8,2,8,2,9,2,11,3,1,4,1,7,2,11,4,1,6,2,12,

%U 4,1,9,3,1,8,3,1,8,3,1,9,4,2,12,5,2,1,8,4,2,1,7,3,2,1,7,4,2,1,9,5,3,1,1

%N a(n) = leading digit of n! in base 13.

%H David A. Corneth, <a href="/A136763/b136763.txt">Table of n, a(n) for n = 0..9999</a>

%e a(10) = 9 as 10! = 9100926_13 which has leading digit 9. - _David A. Corneth_, Jan 15 2021

%t Table[First[IntegerDigits[n!,13]],{n,0,100}] (* _Harvey P. Dale_, Dec 20 2015 *)

%o (PARI) a(n) = digits(n!, 13)[1]; \\ _Michel Marcus_, Jan 27 2015

%Y Cf. A000142, A136699, A136754, A136755, A136756, A136757, A136758, A136759, A136760, A008905, A136761, A136762, A136764, A136765, A136766.

%K nonn,easy,base

%O 0,3

%A _Carl R. White_, Jan 21 2008