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%I #6 Feb 17 2017 19:49:42
%S 0,1,4,6,21,59,239,760,2970,10060,38930,124735,503767,1986024,7059818,
%T 27806989,107739266,376458328,1421570461,5750402871,23095812036,
%U 89360066340,315720338715,1202284699132,5133364318360,20343420316531,74430884941912,279471388089807
%N Number of n-element subsets of [2n] having a prime element sum.
%H Alois P. Heinz, <a href="/A282517/b282517.txt">Table of n, a(n) for n = 0..130</a>
%F a(n) = A282516(2n,n).
%e a(1) = 1: {2}.
%e a(2) = 4: {1,2}, {1,4}, {2,3}, {3,4}.
%e a(3) = 6: {1,2,4}, {1,4,6}, {2,3,6}, {2,4,5}, {2,5,6}, {3,4,6}.
%e a(4) = 21: {1,2,3,5}, {1,2,3,7}, {1,2,4,6}, {1,2,6,8}, {1,3,4,5}, {1,3,5,8}, {1,3,6,7}, {1,3,7,8}, {1,4,5,7}, {1,4,6,8}, {1,5,6,7}, {2,3,4,8}, {2,3,5,7}, {2,3,6,8}, {2,4,5,6}, {2,4,5,8}, {2,4,6,7}, {2,6,7,8}, {3,4,5,7}, {3,5,7,8}, {4,5,6,8}.
%Y Cf. A282516.
%K nonn
%O 0,3
%A _Alois P. Heinz_, Feb 17 2017
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