OFFSET
0,2
COMMENTS
Yin et al. prove that a(n) is never a square for n > 0.
LINKS
Q. Yin, Q. Tan and Y. Luo, p-Adic Valuation of (12+21)...(n2+21) and Applications, Southeast Asian Bulletin of Mathematics, Vol. 39(5) (2015) page: 747-754.
MATHEMATICA
Table[Product[k^2 + 21, {k, n}], {n, 0, 16}] (* Michael De Vlieger, Apr 03 2016 *)
PROG
(PARI) a(n) = prod(k=1, n, (k^2+21));
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Marcus, Apr 03 2016
STATUS
approved