Antidiagonal sums of triangle A118185: a(n) = Sum_{k=0..[n/2]} 4^(k*(n-2*k)) for n>=0.

A118187

Antidiagonal sums of triangle A118185: a(n) = Sum_{k=0..[n/2]} 4^(k*(n-2*k)) for n>=0.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =5a(4) =18a(5) =81a(6) =514a(7) =5185a(8) =73730a(9) =1327361a(10) =33685506a(11) =1359217665a(12) =77311508482

External references