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A176049
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Primes of the form n!*(n+1)!*(n+2)! - 1 or n!*(n+1)!*(n+2)! + 1.
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0
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OFFSET
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1,1
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COMMENTS
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Primes of the form A010790(k)-1 or A010790(k)+1. This is the 3rd sequence in the supersequence whose first member is factorial primes, A002981 UNION A002982, and whose 2nd member is A176038 Primes of the form n!*(n+1)! - 1 or n!*(n+1)! + 1.
a(9) has already 486 digits and is not listed for that reason. The sequence is generated by the n-values 0, 1, 1, 4, 6, 9, 13, 19, 101, 196,... [From R. J. Mathar, Oct 03 2010]
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LINKS
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EXAMPLE
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a(2) = 11 because 1!*(1+1)!*(1+2)! - 1 = 11 is prime. a(4) = 2073601 because 4!*(4+1)!*(4+2)! + 1 = 2073601 is prime. a(7) because 13!*(13+1)!*(13+2)! - 1 = 709885457731229765106401279999999 is prime.
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MATHEMATICA
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Select[Union[Flatten[Times@@#+{1, -1}&/@Partition[Range[0, 30]!, 3, 1]]], PrimeQ] (* Harvey P. Dale, Jan 05 2013 *)
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CROSSREFS
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KEYWORD
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easy,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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