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 A087821 Sequence of primes P(i) such that P=(j*P(i)#)/2 - 2 and P+4 are consecutive primes, where j is odd, 0 < j < P(i+1) and P(i) denotes i-th prime. 2
 3, 5, 5, 7, 7, 11, 13, 13, 13, 17, 17, 23, 29, 31, 31, 43, 43, 47, 53, 53, 61, 73, 83, 89, 89, 103, 131, 131, 173, 223, 227, 241, 251, 257, 311, 331, 359, 443, 523 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS I think I have a proof that the sequence is infinite. LINKS EXAMPLE (3*2*3*5*7*11*13*17)/2 - 2 = 765763 and (3*2*3*5*7*11*13*17)/2 + 2 = 765767 are gap 4 primes, with j=3, i=7, P(i)=17. CROSSREFS Cf. A087820, A087822. Sequence in context: A242189 A302756 A305216 * A204894 A109258 A088081 Adjacent sequences:  A087818 A087819 A087820 * A087822 A087823 A087824 KEYWORD nonn,more AUTHOR Pierre CAMI, Oct 06 2003 EXTENSIONS Edited by Ray Chandler, Oct 19 2003 STATUS approved

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Last modified September 26 05:00 EDT 2020. Contains 337346 sequences. (Running on oeis4.)