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 A139460 a(n) = m such that 2*prime(n+m+1) + (product of n successive odd primes) is prime. 4
 1, 1, 1, 1, 2, 3, 3, 1, 1, 2, 1, 1, 9, 2, 7, 21, 7, 25, 4, 3, 18, 7, 4, 7, 11, 5, 1, 1, 61, 5, 20, 6, 22, 16, 11, 17, 1, 70, 6, 5, 5, 22, 9, 52, 108, 16, 1, 32, 42, 15, 5, 66, 6, 8, 3, 38, 17, 4, 23, 93, 8, 16, 6, 1, 39, 7, 9, 10, 21, 57, 40, 2, 15, 39, 16, 7, 5, 13, 138, 95, 58, 8, 47, 11, 39 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 COMMENTS Or, a(n) = m such that primorial(n+1)/2+2*prime(n+m+1) is prime. For positions of 1's in this sequence see A139461 LINKS MATHEMATICA k = 1; a = {}; Do[k = k*Prime[n]; m = 1; While[ ! PrimeQ[k + 2*Prime[n + m]], m++ ]; Print[m]; AppendTo[a, m], {n, 2, 200}]; a (*Artur Jasinski*) CROSSREFS Cf. A067026, A067027, A139439, A139440, A139441, A139442, A139443, A139444, A139445, A139446, A139447, A139448, A139449, A139450, A139451, A139452, A139453, A139454, A139455, A139456, A139457, A103514, A139460, A139461, A139462, A139463. Sequence in context: A171872 A005135 A290003 * A105244 A257451 A209007 Adjacent sequences:  A139457 A139458 A139459 * A139461 A139462 A139463 KEYWORD nonn AUTHOR Artur Jasinski, Apr 22 2008; definition corrected May 09 2008 STATUS approved

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Last modified April 11 21:52 EDT 2021. Contains 342888 sequences. (Running on oeis4.)