A125174 Primes of the form k! + (k+1)! - 1.

2, 7, 29, 839, 3991679, 93405311999, 1394852659199, 6758061133823999, 315777214062132212662271999999, 9146650338351415815045119999999, 303916116658416027343136804044799999999, 836313165329095177704251551336018791628799999999

Offset

1,1

Comments

Next term is too long (167 digits) to include in data. - James C. McMahon, Dec 11 2024

Links

Table of n, a(n) for n=1..12.

Example

0!+1!-1 = 1 is not prime, 1!+2!-1 = 2 is prime, 2!+3!-1 = 7 is prime, 3!+4!-1 = 29 is prime, 4!+5!-1 = 143 = 11*13 is not prime.

Mathematica

Select[Table[n!+(n+1)!-1, {n, 110}], PrimeQ] (* James C. McMahon, Dec 11 2024 *)

Prog

(PARI) for(n=0, 35, if(isprime(a=n!+(n+1)!-1), print1(a, ", ")))

Crossrefs

Cf. A087146 (values of k), A118913 (primes of the form k! + (k+1)! + 1).

Sequence in context: A359950 A094475 A093034 * A270526 A037417 A042913

Adjacent sequences: A125171 A125172 A125173 * A125175 A125176 A125177

Keyword

nonn

Author

Tomas Xordan, Jan 12 2007

Extensions

Edited and extended by Klaus Brockhaus, Jan 24 2007

a(12) from James C. McMahon, Dec 11 2024

Status

approved