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Search: id:A126807
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| A126807 |
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Numbers n such that partial sum of Catalan numbers A014138(n) is a prime. |
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OFFSET
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1,2
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MAPLE
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s[0]:=1: for n to 1000 do s[n]:= s[n-1]+binomial(2*n+2, n+1)/(n+2) end do: a:= proc (n) if isprime(s[n]) = true then n else end if end proc: seq(a(n), n= 0.. 1000); -Emeric Deutsch (deutsch(AT)duke.poly.edu), Aug 28 2007
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MATHEMATICA
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s = 0; Do[s = s + (2n)!/n!/(n+1)!; If[ PrimeQ[s], Print[n-1]], {n, 200}]
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CROSSREFS
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Cf. A014138, A000108. Cf. A014137, A121852 = numbers n such that partial sum of Catalan numbers A014137(n) is a prime.
Adjacent sequences: A126804 A126805 A126806 this_sequence A126808 A126809 A126810
Sequence in context: A024869 A108940 A007939 this_sequence A091632 A060768 A060809
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KEYWORD
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more,nonn
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AUTHOR
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Alexander Adamchuk (alex(AT)kolmogorov.com), Feb 23 2007
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EXTENSIONS
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3 more terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Aug 28 2007
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