login
This site is supported by donations to The OEIS Foundation.

 

Logo

Annual Appeal: Please make a donation to keep the OEIS running. In 2018 we replaced the server with a faster one, added 20000 new sequences, and reached 7000 citations (often saying "discovered thanks to the OEIS").
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A045521 n! has initial digit '2'. 18
2, 4, 16, 20, 23, 30, 32, 34, 39, 44, 47, 54, 58, 68, 75, 85, 86, 87, 113, 114, 115, 126, 135, 142, 148, 153, 159, 163, 168, 172, 180, 184, 188, 195, 205, 208, 211, 214, 217, 220, 223, 226, 234, 237, 242, 247, 252, 257, 262, 269, 276, 278, 287, 289, 302, 304 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Chai Wah Wu, Table of n, a(n) for n = 1..10000

Index entries for sequences related to factorial numbers

MATHEMATICA

Select[ Range[ 310 ], IntegerDigits[ #! ] [ [ 1 ] ] == 2 & ]

PROG

(PARI) isok(n) = digits(n!)[1] == 2; \\ Michel Marcus, Feb 07 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. See also A000142.

Sequence in context: A229238 A212202 A102545 * A242205 A076434 A192150

Adjacent sequences:  A045518 A045519 A045520 * A045522 A045523 A045524

KEYWORD

nonn,base

AUTHOR

Jeff Burch

EXTENSIONS

Offset changed to 1 by Chai Wah Wu, Feb 07 2017

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 13 22:07 EST 2018. Contains 318087 sequences. (Running on oeis4.)