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A262204
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a(n) = (2*prime(n))! / prime(n)!.
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1
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12, 120, 30240, 17297280, 28158588057600, 64764752532480000, 830034394580628357120000, 4299578163927654889881600000, 212850788988365112429784203264000000, 265847614191284935213187014536606662000640000000
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OFFSET
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1,1
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COMMENTS
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Inspired by simplicity of sequence formula that is (p + p)!/p! where p is n-th prime number.
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LINKS
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FORMULA
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EXAMPLE
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For n=1, a(n) = (2*prime(n))! / prime(n)! = 4!/2! = 3*4 = 12.
For n=2, a(n) = (2*prime(n))! / prime(n)! = 6!/3! = 4*5*6 = 120.
For n=3, a(n) = (2*prime(n))! / prime(n)! = 10!/5! = 6*7*8*9*10 = 30240.
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PROG
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(PARI) a(n) = (2*prime(n))!/prime(n)!;
vector(10, n, a(n))
(Magma) [Factorial(NthPrime(n)+NthPrime(n)) / Factorial(NthPrime(n)): n in [1..10]]; // Vincenzo Librandi, Sep 16 2015
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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