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.
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
KEYWORD
nonn
AUTHOR
Tom Edgar, Mar 24 2014
STATUS
approved