89670

Appears in sequences

• Triangle T, read by rows, where row n+1 of T = row n of matrix power T^(2n) with appended '1' for n>=0 with T(0,0)=1.at n=39A132610
• Number of n X n symmetric binary matrices with every 1 adjacent horizontally (and vertically) to some other 1.at n=6A140363
• G.f.: A(x) = Sum_{n>=0} x^n/[Sum_{k=0..n} C(n,k)^2*(-x)^k].at n=8A178324