A045509 - OEIS

%I #18 Jul 19 2020 02:12:56

%S 1,120,1307674368000,121645100408832000,1124000727777607680000,

%T 15511210043330985984000000,10888869450418352160768000000,

%U 10333147966386144929666651337523200000000,13763753091226345046315979581580902400000000

%N Factorials having initial digit '1'.

%C Benford's law shows that this sequence will contain about log 2/log 10 =~ 30% of factorials. [_Charles R Greathouse IV_, Nov 13 2010]

%H <a href="/index/Be#Benford">Index entries for sequences related to Benford's law</a>

%F a(n) = A000142(A045520(n+1)). - _Amiram Eldar_, Jul 19 2020

%t Select[Range[40]!,First[IntegerDigits[#]]==1&] (* _Harvey P. Dale_, Aug 06 2013 *)

%Y For factorials with initial digit d (1 <= d <= 9) see A045509, A045510, A045511, A045516, A045517, A045518, A282021, A045519; A045520, A045521, A045522, A045523, A045524, A045525, A045526, A045527, A045528, A045529.

%Y Cf. A000142.

%K nonn,base

%O 1,2

%A _Jeff Burch_

%E Corrected and extended by _Harvey P. Dale_, Aug 06 2013