81360

Appears in sequences

• E.g.f. (1-sqrt(1-4*x-4*x^2))/ (2*(1+x)).at n=6A052726
• Number of reduced 3 X 3 semimagic squares with distinct nonnegative integer entries and maximum entry n.at n=21A173727
• Array read by antidiagonals: T(m,n) = Sum(1<=i<=m) i * ( n + 2(i-1) )!at n=22A211366
• a(n) = [y^(n-1)] Product_{k=0..n-2} (n + k*y + n*y^2) for n > 1 with a(1) = 1.at n=5A324304
• Triangle, read by rows, where the g.f. of row n equals Product_{k=0..n-2} (n + k*y + n*y^2) for n > 1 with a single '1' in row 1.at n=30A324305