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A239682
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Product_{i=1..n} A173557(i).
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1
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1, 1, 2, 2, 8, 16, 96, 96, 192, 768, 7680, 15360, 184320, 1105920, 8847360, 8847360, 141557760, 283115520, 5096079360, 20384317440, 244611809280, 2446118092800, 53814598041600, 107629196083200, 430516784332800, 5166201411993600, 10332402823987200
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OFFSET
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1,3
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COMMENTS
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This is the generalized factorial for A173557.
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LINKS
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Table of n, a(n) for n=1..27.
Donald E. Knuth and Herbert S. Wilf, The power of a prime that divides a generalized binomial coefficient, J. Reine Angew. Math., 396:212-219, 1989.
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FORMULA
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Product_{i=1..n} A173557(i).
a(n) = abs(A085542(n)).
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EXAMPLE
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The first five terms of A173557 are 1,1,2,1,4 so a(5)=4*1*2*1*1=8.
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PROG
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(Sage)
q=50 # change q for more terms
R=[prod([(x-1) for x in prime_divisors(n)]) for n in [1..q]]
[prod(R[0:i+1]) for i in [0..q-1]]
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CROSSREFS
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Cf. A173557, A085542, A048803.
Sequence in context: A016120 A188115 A085542 * A009725 A053098 A354117
Adjacent sequences: A239679 A239680 A239681 * A239683 A239684 A239685
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KEYWORD
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nonn
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AUTHOR
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Tom Edgar, Mar 24 2014
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STATUS
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approved
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