a(n) = denominator of Sum_{k=1..n} 1/k^2.

Terms

a(0) =1a(1) =4a(2) =36a(3) =144a(4) =3600a(5) =3600a(6) =176400a(7) =705600a(8) =6350400a(9) =1270080a(10) =153679680a(11) =153679680a(12) =25971865920a(13) =25971865920a(14) =129859329600a(15) =519437318400