213444

Appears in sequences

• Squares of elements to right of central element in Pascal triangle (by row) that are not 1.at n=20A014720
• Squares of elements to left of the central element in Pascal triangle (by row).at n=30A014721
• Squares of even elements in Pascal's triangle A007318.at n=30A014727
• Squares of even elements in Pascal's triangle A007318.at n=31A014727
• Squares of numbers in array formed from even elements to the right of middle of rows of Pascal triangle.at n=12A014762
• Squares of distinct elements in Pascal triangle.at n=28A014764
• a(n) = binomial(n, floor(n/2))^2 = A001405(n)^2.at n=11A018224
• Number of ways to place a non-attacking white and black rook on n X n chessboard.at n=21A035287
• Triangle T(n,k) (0 <= k <= n) giving number of chains of length k in partially ordered set formed from subsets of n-set by inclusion.at n=39A038719
• Sigma(n) / d(n) is a perfect square associated with A049226.at n=25A049227
• a(0) = 1; for n > 0, binomial(2n-1, n-1)^2.at n=6A060150
• Square associated with twin primes (p,p+2): p(p+2) + 1. Square of the average of twin primes.at n=23A075369
• Square perimeters of primitive Pythagorean triangles.at n=17A120089
• a(1)=1; at n>=2, a(n) = least square > a(n-1) such that sum a(1)+...+a(n) is a prime number.at n=21A139033
• Squares whose decimal expansion contains no digit greater than 4.at n=39A158082
• Numbers with prime factorization p^2*q^2*r^2*s^2 where p, q, r, and s are distinct primes.at n=3A190377
• Norm of coefficients in g.f. C(x) that satisfies: C(x) = 1 + x/C(I*x).at n=24A193384
• Number of 2 X n 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 1 0 1 vertically.at n=16A207025
• Number of 4Xn 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 1 1 and 1 0 1 vertically.at n=9A207764
• Number of nX6 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 1 0 and 1 1 1 vertically.at n=10A209222