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 A239682 Product_{i=1..n} A173557(i). 1
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS This is the generalized factorial for A173557. LINKS 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. FORMULA Product_{i=1..n} A173557(i). a(n) = abs(A085542(n)). EXAMPLE The first five terms of A173557 are 1,1,2,1,4 so a(5)=4*1*2*1*1=8. PROG (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]] CROSSREFS Cf. A173557, A085542, A048803. Sequence in context: A016120 A188115 A085542 * A009725 A053098 A354117 Adjacent sequences:  A239679 A239680 A239681 * A239683 A239684 A239685 KEYWORD nonn AUTHOR Tom Edgar, Mar 24 2014 STATUS approved

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Last modified August 7 12:01 EDT 2022. Contains 355985 sequences. (Running on oeis4.)