253000

Appears in sequences

• Numbers n such that n^2 can be split into two nonzero squares (perhaps with leading zeros) in exactly two different ways.at n=21A054737
• Sum of lists created by n substitutions k -> Range[k+1,0,-2] starting with {0}, counting down from k+1 to 0 step -2.at n=16A084081
• Triangle read by rows: T(n,k) is number of leaves at level k in all noncrossing rooted trees on n+1 nodes.at n=37A101372
• a(n) = binomial(n+2,3)*5^3.at n=21A141480
• Triangle read by rows: T(n,m) is the number of pattern classes in the (n,m)-rectangular grid with 10 colors and n>=m, two patterns are in the same class if one of them can be obtained by a reflection or 180-degree rotation of the other.at n=8A286921