a(n) = Sum_{k=0..n} C(n,k)*3^(k*(n-k))/2^n.
A172389
a(n) = Sum_{k=0..n} C(n,k)*3^(k*(n-k))/2^n.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =7a(4) =44a(5) =481a(6) =9272a(7) =310087a(8) =18164624a(9) =1843946881a(10) =326808099872
External references
- oeis: A172389