1019592

Appears in sequences

• a(n) is the number of 2 X 1 domino tilings of the set S in the plane R^2 consisting of the union of the following two rectangles: rectangle1: |x| <= n, |y| <= 1, rectangle2: |x| <= 1, |y| <= n.at n=7A060635
• Numbers with prime factorization p^2*q^2*r^2*s^3 where p, q, r, and s are distinct primes.at n=19A190382