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A057034
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Difference between n!! and the first prime before n!! - 1.
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2
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3, 2, 5, 2, 5, 4, 7, 4, 7, 4, 23, 2, 19, 2, 97, 2, 19, 64, 17, 62, 19, 4, 17, 58, 23, 64, 157, 122, 47, 106, 47, 4, 29, 146, 31, 64, 29, 8, 71, 8, 43, 32, 31, 128, 67, 122, 41, 2, 37, 146, 137, 122, 191, 142, 59, 128, 71, 284, 109, 274, 101, 218, 97, 32, 83, 158, 53, 166
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OFFSET
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4,1
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COMMENTS
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Analogous to the lesser Fortunate numbers but unlike them, all entries are not prime. Must odd entries are powers of two and all even entries are primes.
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LINKS
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MATHEMATICA
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PrevPrime[ n_Integer ] := (k=n-1; While[ !PrimeQ[ k ], k-- ]; Return[ k ]); f[ n_Integer ] := (p = n!! - 1; q = PrevPrime[ p ]; Return[ p - q + 1 ]); Table[ f[ n ], {n, 4, 75} ]
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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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