OFFSET
0,2
COMMENTS
Smallest integer of the form 'Product of first n composite number/ product of first k primes'.
Divide Compositorial(n) by Primorial(k) choosing k to give the smallest integer. (k+1)-th prime does not divide a(n).
EXAMPLE
a(0) = 1, a(5) = (4*6*8*9*10)/(2*3*5) = 576, 10 is the fifth composite number.
MATHEMATICA
Composite[n_] := FixedPoint[n + PrimePi[ # ] + 1 &, n + PrimePi[n] + 1]; PrimeFactors[n_] := Flatten[ Table[ # [[1]], {1}] & /@ FactorInteger[n]]; Table[ Product[ Composite[i], {i, 1, n}]/ Times @@ PrimeFactors[ Product[ Composite[i], {i, 1, n}]], {n, 0, 20}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Sep 08 2002
EXTENSIONS
Edited and extended by Robert G. Wilson v, Jul 15 2003
Further edited by N. J. A. Sloane, Sep 13 2008 at the suggestion of R. J. Mathar
STATUS
approved