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%I #20 Jul 17 2020 05:36:24
%S 3,13,18,24,43,49,72,120,130,138,174,178,182,193,203,227,263,270,290,
%T 309,311,313,315,317,319,321,355,364,371,378,390,395,400,405,418,426,
%U 437,457,460,463,466,469,491,501,511,518,525,536,555,559,563,567,571
%N Numbers k such that k! has initial digit '6'.
%C The asymptotic density of this sequence is log_10(7/6) = 0.066946... (Kunoff, 1987). - _Amiram Eldar_, Jul 17 2020
%H Chai Wah Wu, <a href="/A045525/b045525.txt">Table of n, a(n) for n = 1..10000</a>
%H Sharon Kunoff, <a href="https://www.fq.math.ca/Scanned/25-4/kunoff.pdf">N! has the first digit property</a>, The Fibonacci Quarterly, Vol. 25, No. 4 (1987), pp. 365-367.
%H <a href="/index/Fa#factorial">Index entries for sequences related to factorial numbers</a>
%F A008905(a(n)) = 6. - _Amiram Eldar_, Jul 17 2020
%e 3 is a term since 3! = 6 has the initial digit 6.
%t Select[ Range[ 600 ], IntegerDigits[ #! ] [ [1] ] == 6 & ]
%o (PARI) isok(n) = digits(n!)[1] == 6; \\ _Michel Marcus_, 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, A008905.
%K nonn,base
%O 1,1
%A _Jeff Burch_
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