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%I #21 Jul 17 2020 05:32:15
%S 6,56,80,156,161,170,186,200,230,238,277,288,305,307,323,325,327,344,
%T 385,410,451,454,472,475,504,532,547,551,575,592,601,615,645,661,697,
%U 710,724,731,790,800,811,822,848
%N Numbers k such that k! has initial digit '7'.
%C The asymptotic density of this sequence is log_10(8/7) = 0.057991... (Kunoff, 1987). - _Amiram Eldar_, Jul 17 2020
%H Chai Wah Wu, <a href="/A045526/b045526.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)) = 7. - _Amiram Eldar_, Jul 17 2020
%e 6 is a term since 6! = 720 has the initial digit 7.
%t Select[ Range[ 900 ], IntegerDigits[ #! ] [[1]] == 7 & ]
%o (PARI) isok(n) = digits(n!)[1] == 7; \\ _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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