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A136402
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Prime Wedderburn-Etherington numbers.
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0
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2, 3, 11, 23, 983, 2179, 24631, 3626149, 253450711, 596572387, 4958179972866730572551, 17950473826186485808766524097, 17690812163571687513245304152178763697755384812733, 9852801774222802457119814738073136914072348071335480633169417277909155746150705781482843
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OFFSET
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1,1
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COMMENTS
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Corresponding indices are 4, 5, 7, 8, 13, 14, 17, 23, 28, 29, 63, 80, 134, 233, 534, 732, 1963, 3896, 7792, 7987, 8312, ... with no more up to 2*10^4. - Charles R Greathouse IV, Mar 23 2014
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LINKS
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MATHEMATICA
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a[n_?OddQ] := a[n] = Sum[a[k]*a[n - k], {k, 1, (n - 1)/2}]; a[n_?EvenQ] := a[n] = Sum[a[k]*a[n - k], {k, 1, n/2 - 1}] + (1/2)*a[n/2]*(1 + a[n/2]); a[0] = 0; a[1] = 1; Select[a@# & /@ Range@ 300, PrimeQ@# &] (* Robert G. Wilson v, May 20 2014, after Jean-François Alcover in A001190 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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