A282021 - OEIS

%I #19 Jul 19 2020 02:34:44

%S 720,

%T 710998587804863451854045647463724949736497978881168458687447040000000000000,

%U 71569457046263802294811533723186532165584657342365752577109445058227039255480148842668944867280814080000000000000000000

%N Factorials with initial digit '7'.

%C Benford's law shows that this sequence will contain about (log(8) - log(7))/log(10) =~ 5.8% of all factorials.

%H Vincenzo Librandi, <a href="/A282021/b282021.txt">Table of n, a(n) for n = 1..22</a>

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

%F a(n) = A000142(A045526(n)). - _Amiram Eldar_, Jul 19 2020

%t Select[Range[100]!, First[IntegerDigits[#]] == 7 &] (* _Vincenzo Librandi_, Feb 08 2017 *)

%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. See also A000142.

%K nonn,base

%O 1,1

%A _N. J. A. Sloane_, Feb 07 2017