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A088332
Primes of the form k! + 1.
20
2, 3, 7, 39916801, 10888869450418352160768000001, 13763753091226345046315979581580902400000001, 33452526613163807108170062053440751665152000000001
OFFSET
1,1
COMMENTS
The next term is too large to include.
Of course 2 = 0! + 1 = 1! + 1 has two such representations.
Prime numbers that are the sum of two factorial numbers. - Juri-Stepan Gerasimov, Nov 08 2010
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..15 (terms 1..11 from T. D. Noe)
Romeo Meštrović, Euclid's theorem on the infinitude of primes: a historical survey of its proofs (300 BC--2012) and another new proof, arXiv preprint arXiv:1202.3670 [math.HO], 2012-2023. - From N. J. A. Sloane, Jun 13 2012
EXAMPLE
3! + 1 = 7 is prime.
MATHEMATICA
lst={}; Do[p=n!+1; If[PrimeQ[p], AppendTo[lst, p]], {n, 0, 3*5!}]; lst (* Vladimir Joseph Stephan Orlovsky, Jan 27 2009 *)
PROG
(PARI) factp1prime(n)=for(x=1, n, xf=x!+1; if(isprime(xf), print1(xf", ")))
CROSSREFS
Cf. A002981 (values of k), A038507, A062701.
Sequence in context: A196303 A048979 A201363 * A357064 A131959 A202688
KEYWORD
nonn
AUTHOR
Cino Hilliard, Nov 06 2003
STATUS
approved