OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..500

EXAMPLE

17 is the smallest prime in 17, 19, 23, 29 which is the first chain of four consecutive primes whose product + 2 is prime: 17 * 19 * 23 * 29 + 2 = 215443 (prime). Hence a(4) = 17.

MATHEMATICA

pl=Prime[Range[1000]]; frp[n_] := Module[{pl2=Partition[pl, n, 1]}, First[Select[pl2, PrimeQ[(Times@@#)+2]&][[1]]]]; Table[frp[i], {i, 25}]

CROSSREFS

KEYWORD

nonn

AUTHOR

Joseph L. Pe, Jun 12 2003

EXTENSIONS

More terms from Amiram Eldar, Sep 29 2019

STATUS

approved