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A168177
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Number of prime factors of n! + 2^n - 1, counted with multiplicity.
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2
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1, 1, 1, 2, 1, 4, 1, 4, 2, 4, 1, 5, 4, 4, 4, 4, 2, 7, 2, 8, 4, 3, 3, 7, 3, 3, 5, 6, 5, 7, 3, 7, 5, 6, 3, 10, 5, 8, 4, 8, 7, 7, 9, 6, 5, 5, 4, 11, 5, 6, 3, 6, 4, 9, 6, 11, 5, 2, 4, 15, 2, 6, 5, 8, 5, 7, 4, 5, 7, 9, 2, 13, 7, 5, 8, 6, 4, 7, 3, 11, 5, 3, 3, 11, 6
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OFFSET
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1,4
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LINKS
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FORMULA
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EXAMPLE
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6! + 2^6 - 1 = 783 = 3^3 * 29, hence a(6) = 4.
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MATHEMATICA
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PrimeOmega @ Table[n! + 2^n - 1, {n, 1, 30}] (* Amiram Eldar, Feb 05 2020 *)
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PROG
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(Magma) pfmult := func< n | &+[ d[2]: d in Factorization(n) ] >; [ pfmult(Factorial(n)+2^n-1): n in [1..50] ]; //Some values were computed using Dario Alpern's ECM Factorization Program.
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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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