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%I #22 Jan 17 2021 04:29:53
%S 3,4,5,7,11,13,17,19,23,31,43,61,79,101,127,167,191,199,313,347,701,
%T 1709,2617,3539,5807,10501,10691,11279,12391,14479,42737,83339,95369,
%U 117239,127031,138937,141079,267017,269987,374321
%N Indices of prime Jacobsthal numbers.
%C All terms are prime except a(1) = 4. All prime terms are listed in A000978. - _Alexander Adamchuk_, Oct 03 2006
%F a(n) = A000978(n-1) for n >= 3. - _Alexander Adamchuk_, Oct 03 2006
%o (PARI) is(n)=ispseudoprime((2^n - (-1)^n) / 3) \\ _Charles R Greathouse IV_, Apr 28 2015
%Y Cf. A000978, A001045, A001605.
%K nonn
%O 1,1
%A _Paul Barry_, May 09 2005
%E More terms from _Alexander Adamchuk_, Oct 03 2006
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