A282021 Factorials with initial digit '7'.

720, 710998587804863451854045647463724949736497978881168458687447040000000000000, 71569457046263802294811533723186532165584657342365752577109445058227039255480148842668944867280814080000000000000000000

Offset: 1

Author

N. J. A. Sloane, Feb 07 2017

Keywords

• nonn
• base

Comments

Benford's law shows that this sequence will contain about (log(8) - log(7))/log(10) =~ 5.8% of all factorials.

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..22
• Index entries for sequences related to Benford's law

Crossrefs

For factorials with initial digit d (1 <= d <= 9) see A045509, A045510, A045511, A045516, A045517, A045518, A282021, A045519; A045520, A045521, A045522, A045523, A045524, A045525, A045526, A045527, A045528, A045529. See also A000142.

Programs

Mathematica

Select[Range[100]!, First[IntegerDigits[#]] == 7 &] (* Vincenzo Librandi, Feb 08 2017 *)

Formula

a(n) = A000142(A045526(n)). - Amiram Eldar, Jul 19 2020