OFFSET
1,1
COMMENTS
The asymptotic density of this sequence is log_10(5/4) = 0.096910... (Kunoff, 1987). - Amiram Eldar, Jul 17 2020
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..10000
Sharon Kunoff, N! has the first digit property, The Fibonacci Quarterly, Vol. 25, No. 4 (1987), pp. 365-367.
FORMULA
A008905(a(n)) = 4. - Amiram Eldar, Jul 17 2020
EXAMPLE
8 is a term since 8! = 40320 has the initial digit 4.
MATHEMATICA
Select[ Range[ 700 ], IntegerDigits[ #! ] [[ 1 ]] == 4 & ]
PROG
(PARI) isok(n) = digits(n!)[1] == 4; \\ Michel Marcus, Feb 07 2017
CROSSREFS
KEYWORD
nonn,base
AUTHOR
STATUS
approved