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 A243310 Smallest k such that both prime(k)*prime(k+1) +/- 2^n are prime, or 0 if no such k exists. 0
 1, 2, 2, 2, 0, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS a(n) = 0 for n > 5? a(n) = 0 for 5 < n <= 10000. Heuristics suggest that there are no other nonzero terms. - Charles R Greathouse IV, Jun 04 2014 LINKS EXAMPLE a(0) = 1 because prime(1)*prime(1+1)-2^0 = 5 and prime(1)*prime(1+1) + 2^0 = 7 are prime, a(1) = 2 because prime(2)*prime(2+1)-2^1 = 13 and prime(2)*prime(2+1)+2^1 = 17 are prime, a(2) = 2 because prime(2)*prime(2+1)-2^2 = 11 and prime(2)*prime(2+1)+2^2 = 19 are prime, a(3) = 2 because prime(2)*prime(2+1)-2^3 = 7 and prime(2)*prime(2+1)+2^3 = 23 are prime. CROSSREFS Cf. A006094. Sequence in context: A059288 A319109 A217670 * A197727 A176884 A071443 Adjacent sequences:  A243307 A243308 A243309 * A243311 A243312 A243313 KEYWORD nonn,less AUTHOR Juri-Stepan Gerasimov, Jun 03 2014 STATUS approved

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Last modified October 16 03:43 EDT 2018. Contains 316259 sequences. (Running on oeis4.)