57324

Appears in sequences

• a(n+3) = a(n+2) + 3a(n+1) - 2a(n); a(0) = 1, a(1) = -1, a(2)= 3.at n=18A104005
• Triangle read by rows, M * Q; M = (T(n,k) = A155728(n-k+1)); Q = (A155728 * 0^(n-k)).at n=36A155729
• Draw a square and follow these steps: Take a square and place at its edges isosceles right triangles with the edge as hypotenuse. Draw a square at every new edge of the triangles. Repeat for all the new squares of the same size. New figures are only placed on empty space. The structure is symmetric about the first square. The sequence gives the numbers of squares of equal size in successive rings around the center.at n=23A265207
• Number of n X 2 0..1 arrays with rows in nondecreasing lexicographic order and columns in nonincreasing lexicographic order, but with exactly one mistake.at n=15A278670
• Number of length n inversion sequences avoiding the patterns 100 and 120.at n=9A374549
• a(n) is the number of 2 X 2 matrices with elements 1..n where at least one row and at least one column is strictly increasing.at n=18A390922