A057050 Let R(i,j) be the rectangle with antidiagonals 1; 2,3; 4,5,6; ...; each k is an R(i(k),j(k)) and A057050(n)=j(n^2).
1, 3, 2, 6, 4, 1, 7, 3, 11, 6, 16, 10, 3, 15, 7, 21, 12, 2, 18, 7, 25, 13, 33, 20, 6, 28, 13, 37, 21, 4, 30, 12, 40, 21, 1, 31, 10, 42, 20, 54, 31, 7, 43, 18, 56, 30, 3, 43, 15, 57, 28, 72, 42, 11, 57, 25, 73, 40, 6, 56, 21, 73, 37, 91, 54, 16, 72
Offset: 1