53335593025domain: NAppears in sequencesDenominator of 2n/v(n)^2, where v(1) = 0, v(2) = 1, and v(n) = v(n-1)/(n-2) + v(n-2) for n >= 3. (Limit of 2n/v(n)^2 is Pi.)at n=20A239225a(n) = denominator((2^n*(n!)^2/(1+2*n)!)^2).at n=9A392619