A045520 - OEIS

A045520

Numbers k such that k! has initial digit '1'.

0, 1, 5, 15, 19, 22, 25, 27, 35, 37, 42, 45, 48, 51, 55, 59, 63, 64, 69, 70, 76, 77, 78, 88, 89, 90, 91, 92, 93, 94, 95, 104, 105, 106, 107, 108, 109, 110, 111, 112, 123, 124, 125, 132, 133, 134, 140, 141, 146, 147, 152, 157, 158, 162, 167, 171, 175, 176, 179, 183

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OFFSET

1,3

COMMENTS

The asymptotic density of this sequence is log_10(2) = 0.301029... (A007524) (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.

Index entries for sequences related to factorial numbers

FORMULA

A008905(a(n)) = 1. - Amiram Eldar, Jul 17 2020

EXAMPLE