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A045510
Factorials having initial digit '2'.
19
2, 24, 20922789888000, 2432902008176640000, 25852016738884976640000, 265252859812191058636308480000000, 263130836933693530167218012160000000
(list; graph; refs; listen; history; text; internal format)
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
Table of n, a(n) for n=1..7.
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
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.
Cf. A000142.
Sequence in context: A159932 A100010 A319761 * A226325 A065665 A321350
Adjacent sequences: A045507 A045508 A045509 * A045511 A045512 A045513
KEYWORD
nonn,base
AUTHOR
Jeff Burch
STATUS
approved

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Last modified January 26 16:35 EST 2025. Contains 380270 sequences.
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