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A282517 Number of n-element subsets of [2n] having a prime element sum. 2
0, 1, 4, 6, 21, 59, 239, 760, 2970, 10060, 38930, 124735, 503767, 1986024, 7059818, 27806989, 107739266, 376458328, 1421570461, 5750402871, 23095812036, 89360066340, 315720338715, 1202284699132, 5133364318360, 20343420316531, 74430884941912, 279471388089807 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..130

FORMULA

a(n) = A282516(2n,n).

EXAMPLE

a(1) = 1: {2}.

a(2) = 4: {1,2}, {1,4}, {2,3}, {3,4}.

a(3) = 6: {1,2,4}, {1,4,6}, {2,3,6}, {2,4,5}, {2,5,6}, {3,4,6}.

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}.

CROSSREFS

Cf. A282516.

Sequence in context: A026722 A229743 A151520 * A227249 A002270 A286358

Adjacent sequences:  A282514 A282515 A282516 * A282518 A282519 A282520

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Feb 17 2017

STATUS

approved

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Last modified May 22 15:30 EDT 2017. Contains 286876 sequences.