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A053429
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Numbers n such that Catalan(n)+1 is prime.
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4
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0, 1, 2, 5, 11, 25, 69, 86, 90, 95, 104, 145, 203, 215, 227, 291, 309, 322, 337, 407, 480, 792, 823, 919, 1001, 1159, 2226, 2743, 2822, 4250, 8077, 8109, 16024, 17422, 23941, 25212, 25379, 28753, 30510, 31748, 33613, 45622
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OFFSET
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1,3
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COMMENTS
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Primality up to Catalan(4250)+1 proved by PrimeForm.
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LINKS
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EXAMPLE
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Catalan(25)+1 = 50!/25!/26!+1 = 4861946401453 is prime.
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MATHEMATICA
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Reap[ Do[ If[ PrimeQ[ CatalanNumber[n] + 1], Print[n]; Sow[n]], {n, 0, 10^4}]][[2, 1]] (* Jean-François Alcover, Feb 02 2015 *)
Select[Range[0, 29000], PrimeQ[CatalanNumber[#]+1]&] (* Harvey P. Dale, Apr 14 2019 *)
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PROG
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(PFGW) ABC2 C(2*$a, $a)/($a+1)+1
a: from 0 to 100000
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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