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A264688 The decimal digits of n appear n times in the decimal representation of n!. 0

%I

%S 0,1,1170,1528,9877,9886,9897,11535

%N The decimal digits of n appear n times in the decimal representation of n!.

%C There are no more terms up to n=21000, checked using the Python program below.

%C a(9) > 200000. - _Dana Jacobsen_, Jan 03 2016

%e 1170 belongs to this sequence because the digits 1, 7 and 0 appear 1170 times in total in the decimal representation of 1170!.

%e 0! = 1, which contains no zeros, so 0 is a term.

%o (Python)

%o from math import factorial

%o def in_a(n):

%o ....f = str(factorial(n))

%o ....s = set(str(n))

%o ....return sum(f.count(d) for d in s)==n

%o (Perl) use ntheory ":all"; sub is_a264688 { my $n = shift; $n == eval "factorial($n) =~ tr/[$n]//"; } # _Dana Jacobsen_, Jan 03 2016

%K nonn,base,more

%O 1,3

%A _Christian Perfect_, Jan 03 2016

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Last modified September 27 22:36 EDT 2020. Contains 337388 sequences. (Running on oeis4.)