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!)
A154664 Numbers n such that n!^2-+7493 are primes. 1
3, 4, 5, 6, 12 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Next term is larger than 72

Next term is larger than 1000. - Harvey P. Dale, Feb 03 2016

LINKS

Table of n, a(n) for n=1..5.

MATHEMATICA

lst={}; a=7493; Do[If[PrimeQ[n!^2-a]&&PrimeQ[n!^2+a], AppendTo[lst, n]], {n, 3*4!}]; lst

Select[Range[20], AllTrue[(#!)^2+{7493, -7493}, PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Feb 03 2016 *)

CROSSREFS

Cf. A144046, A154660, A154661, A154662, A154663

Sequence in context: A048989 A299299 A103402 * A191750 A034448 A069184

Adjacent sequences:  A154661 A154662 A154663 * A154665 A154666 A154667

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, Jan 13 2009

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 11 20:17 EST 2018. Contains 318051 sequences. (Running on oeis4.)