Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the 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