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A264688
The decimal digits of n appear n times in the decimal representation of n!.
0
0, 1, 1170, 1528, 9877, 9886, 9897, 11535
OFFSET
1,3
COMMENTS
There are no more terms up to n=21000, checked using the Python program below.
a(9) > 200000. - Dana Jacobsen, Jan 03 2016
EXAMPLE
1170 belongs to this sequence because the digits 1, 7 and 0 appear 1170 times in total in the decimal representation of 1170!.
0! = 1, which contains no zeros, so 0 is a term.
PROG
(Python)
from math import factorial
def in_a(n):
....f = str(factorial(n))
....s = set(str(n))
....return sum(f.count(d) for d in s)==n
(Perl) use ntheory ":all"; sub is_a264688 { my $n = shift; $n == eval "factorial($n) =~ tr/[$n]//"; } # Dana Jacobsen, Jan 03 2016
CROSSREFS
Sequence in context: A065656 A185468 A209825 * A043432 A065703 A202487
KEYWORD
nonn,base,more
AUTHOR
Christian Perfect, Jan 03 2016
STATUS
approved