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

 

Logo

Annual Appeal: Today, Nov 11 2014, is the 4th anniversary of the launch of the new OEIS web site. 70,000 sequences have been added in these four years, all edited by volunteers. Please make a donation (tax deductible in the US) to help keep the OEIS running.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A108098 Numbers a(n) such that there is no k<=2a(n) with a(n)!+k!-1 prime. 0
48, 63, 68, 74, 111, 129, 135, 161, 168, 174, 197, 236, 240, 243, 273, 279, 282, 285, 309, 322, 335, 347, 360, 393, 407, 419, 431, 437, 439, 440, 455, 460, 461, 483, 491, 494, 497, 512, 517, 522, 526, 532, 544, 567, 591, 614, 625, 650, 662, 663, 681, 687 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

For numbers m <= 320 that are not in the sequence, there exists an integer k <= 2m such that m! + k! - 1 is a certified prime. For m > 320 the values of m! + k! - 1 are only probable primes. - Ryan Propper, Sep 02 2005

LINKS

Table of n, a(n) for n=1..52.

MATHEMATICA

Do[l = Range[1, 2*n]; If[Length[Select[l, PrimeQ[n! + #! - 1]&]] == 0, Print[n]], {n, 1, 729}] (Propper)

CROSSREFS

Cf. A075758.

Sequence in context: A080854 A231469 A114821 * A114505 A186400 A205188

Adjacent sequences:  A108095 A108096 A108097 * A108099 A108100 A108101

KEYWORD

nonn

AUTHOR

Ralf Stephan, Jun 01 2005

EXTENSIONS

More terms from Ryan Propper, Sep 02 2005

STATUS

approved

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

Content is available under The OEIS End-User License Agreement .

Last modified December 19 03:55 EST 2014. Contains 252175 sequences.