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A083562
Beginning of first chain of n consecutive primes whose product + 2 is prime.
2
3, 3, 3, 17, 3, 5, 67, 29, 3, 3, 3, 373, 5, 3, 5, 3, 257, 641, 7, 383, 43, 139, 571, 3967, 2971, 7, 677, 3, 317, 571, 71, 659, 11, 43, 59, 479, 719, 2293, 5, 5237, 1039, 37, 757, 719, 41, 5023, 3, 31, 971, 7, 593, 163, 5003, 1867, 19, 1283, 4549, 17, 4817, 1301
OFFSET
1,1
LINKS
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
Sequence in context: A176248 A290159 A356388 * A332860 A106542 A342363
KEYWORD
nonn
AUTHOR
Joseph L. Pe, Jun 12 2003
EXTENSIONS
More terms from Amiram Eldar, Sep 29 2019
STATUS
approved