A108270 Numbers k such that k*k! + (smallest prime >= k) is prime.

1, 4, 6, 8, 30, 40, 164, 176, 189, 218, 370, 597, 603, 1473, 2176, 2436, 2548, 2732, 4758, 5574

Offset: 1

Author

Jorge Coveiro, Jul 24 2006

Keywords

• nonn
• more
• changed

Comments

Note that Maple, PARI etc. have different notions of what "next prime" means!

Crossrefs

Cf. A096986.

Programs

Mathematica

Select[Range[5600],PrimeQ[# (#!) +NextPrime[#-1]]&] (* Harvey P. Dale, Oct 07 2019 *)

PARI

for(x=1,1000,if(isprime(x*x!+nextprime(x)),print1(x,",")))

Formula

A096986 INTERSECT A018252. - R. J. Mathar, Aug 13 2007

Extensions

a(11)-a(20) from Donovan Johnson, Dec 13 2008