OFFSET
1,3
COMMENTS
Prime factors > sqrt(2)*n occur with multiplicity 1.
EXAMPLE
a(4)=45: A285388(4) = 300540195 = (R(4) = 3*3*5 = 45)*(P(4) = 6678671).
PROG
(PARI) a285388(n) = my(m=n*binomial(2*n^2, n^2)); m>>valuation(m, 2);
a(n) = my(f=factor(a285388(n))); for (k=1, #f~, if (f[k, 1] >= (2/3)*n^2, f[k, 1] = 1)); factorback(f); \\ Michel Marcus, Aug 07 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Ralf Steiner, Aug 07 2017
STATUS
approved