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 A123176 Numbers n such that (2^p + 1)/3 is prime, where p is the n-th prime. 2
 2, 3, 4, 5, 6, 7, 8, 9, 11, 14, 18, 22, 26, 31, 39, 43, 46, 65, 69, 126, 267, 380, 495, 762, 1285, 1304, 1364, 1479, 1697, 4469, 8135, 9193, 11065, 11902, 12923, 13103, 23396, 23642, 31850, 77509, 285228 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Also prime(a(n)) are the indices of prime Jacobsthal numbers (A001045) with prime indices. Primes in the Jacobsthal sequence are listed in A049883. LINKS C. Caldwell's The Top Twenty, Wagstaff. FORMULA a(n) = A000720( A000978(n) ). CROSSREFS Cf. A000978, A000979, A001045, A049883, A107036, A123214. Sequence in context: A082324 A219955 A079064 * A017902 A005710 A291146 Adjacent sequences:  A123173 A123174 A123175 * A123177 A123178 A123179 KEYWORD more,nonn AUTHOR Alexander Adamchuk, Oct 03 2006 EXTENSIONS Two more terms computed from A000978 by Max Alekseyev, Mar 03 2010 STATUS approved

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Last modified February 18 21:20 EST 2020. Contains 332028 sequences. (Running on oeis4.)