login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A290116 Primes of the form k! / 2 - 1. 1
2, 11, 59, 359, 181439, 4111419327088961408862781439999999, 16726263306581903554085031026720375832575999999999 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Robert Price, Table of n, a(n) for n = 1..7

Joe McLean, Interesting Sources of Probable Primes

OpenPFGW Project, Primality Tester

FORMULA

a = (A082671(n)!-2)/2.

EXAMPLE

6! / 2 - 1 = 359, which is prime, so 359 is in the sequence.

7! / 2 - 1 = 2519 = 11 * 229, so 2519 is not in the sequence.

MATHEMATICA

Select[Table[k! / 2 - 1, {k, 2, 100}], PrimeQ[#]&]

CROSSREFS

Cf. A082671, A139172.

Sequence in context: A280674 A139172 A228868 * A251180 A286194 A164034

Adjacent sequences:  A290113 A290114 A290115 * A290117 A290118 A290119

KEYWORD

nonn

AUTHOR

Robert Price, Jul 19 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 September 21 11:09 EDT 2021. Contains 347597 sequences. (Running on oeis4.)