A045510 - OEIS

A045510

Factorials having initial digit '2'.

2, 24, 20922789888000, 2432902008176640000, 25852016738884976640000, 265252859812191058636308480000000, 263130836933693530167218012160000000

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OFFSET

1,1

COMMENTS

Benford's law shows that this sequence will contain about (log 3 - log 2)/log 10 =~ 18% of factorials. [Charles R Greathouse IV, Nov 13 2010]

LINKS

FORMULA

a(n) = A000142(A045521(n)). - Amiram Eldar, Jul 19 2020

MATHEMATICA

Select[Range[50]!, IntegerDigits[#][[1]]==2&] (* Harvey P. Dale, Mar 21 2020 *)

PROG

(PARI) lista(nn) = {for (n=1, nn, if (digits(n!)[1] == 2, print1(n!, ", ")); ); } \\ Michel Marcus, Dec 13 2017

CROSSREFS

KEYWORD

nonn,base

AUTHOR

STATUS

approved