756900

Appears in sequences

• Number of ways to place a non-attacking white and black rook on n X n chessboard.at n=29A035287
• Numbers k such that the numerator of Sum_{d|k} 1/d > 3*k.at n=29A069096
• Define sds(n) = sum of the squares of the digits of n. Sequence gives smaller of two consecutive squares with sds(k^2) = sds((k+1)^2).at n=6A069645
• Square perimeters of primitive Pythagorean triangles.at n=31A120089
• a(n) = (29*n)^2.at n=30A133496
• a(n) = a(n-2) + 2*a(n-3), n > 3; with a(0)=0, a(1)=1, a(2)=2, a(3)=0.at n=34A134271
• Nonnegative integers c such that there are nonnegative integers a and b that satisfy a^(1/2) + b^(1/2) = c^(1/2) and a^2 + b = c.at n=12A135509
• Squares of Bernoulli number denominators A027642.at n=28A172282
• Numbers with prime factorization p^2*q^2*r^2*s^2 where p, q, r, and s are distinct primes.at n=12A190377
• Composite numbers whose number of proper divisors has a number of proper divisors which has a prime number of proper divisors.at n=22A223457
• Areas of primitive Heronian triangles K which are perfect squares.at n=20A248108
• Numbers k such that sigma(k) - 3k is prime.at n=13A306492