a(n) is the length of a side of triangle A068619(n) or a(n) = (sqrt(8*A068619(n) + 1) - 1)/2.

A100243

a(n) is the length of a side of triangle A068619(n) or a(n) = (sqrt(8*A068619(n) + 1) - 1)/2.

Terms

    a(0) =2a(1) =8a(2) =16a(3) =51a(4) =476a(5) =14851a(6) =1484980a(7) =479637019

External references