693693

Appears in sequences

• Successive denominators of Wallis's approximation to Pi/2 (reduced).at n=12A001902
• Number of tree-rooted planar maps with 4 faces and n vertices and no isthmuses.at n=8A006471
• Let W(n) = Product_{k=1..n} (1 - 1/(4*k^2)), the partial Wallis product (lim_{n->oo} W(n) = 2/Pi); then a(n) = numerator(W(n)).at n=6A069955
• Smallest number having n divisors ending with 1 or 9.at n=26A085645
• Highly composite deficient numbers: deficient numbers k whose number of divisors d(k) > d(m) for all deficient numbers m < k.at n=19A302934
• Smallest number having exactly n divisors ending with 3 or 7.at n=26A331082
• a(n) = denominator(r(n)) where r(n) = (n/2)*(Pi/2)^cos(Pi*(n-1))*((n/2-1/2)!/(n/2)!)^2.at n=13A380950