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A087820
Primes P of the form P=(j*P(i)#)/2 - 2 such that P+4 is the next prime, where j is odd, 0 < j < P(i+1), P(i) = i-th prime, P(i)# = i-th primorial (A002110).
3
7, 13, 43, 103, 313, 3463, 15013, 195193, 225223, 765763, 4339333, 3011753743, 9704539843, 100280245063, 2707566616753, 124286232650865283, 150451755314205343, 10760571195298599673, 211829530101735290743
OFFSET
0,1
COMMENTS
I think I have a proof that the sequence is infinite.
EXAMPLE
(27*2*3*5*7*11*13*17*19*23)/2 - 2 = 3011753743 and (27*2*3*5*7*11*13*17*19*23)/2 + 2 = 3011753747 are gap 4 primes, so j=27, i=9, P(i)=23.
CROSSREFS
Cf. A087821, A087822, etc.
Sequence in context: A361914 A047977 A139403 * A272032 A023286 A287685
KEYWORD
nonn
AUTHOR
Pierre CAMI, Oct 06 2003
EXTENSIONS
More terms from Ray Chandler, Oct 19 2003
STATUS
approved