98489

Appears in sequences

• 1/4 the number of n X n arrays of squares of integers with every 2X2 subblock summing to 21.at n=13A159222
• G.f. A(x) satisfies A(x) = 1/( 1 - x*A(x)*(1 + 9*x*A(x))^(1/3) ).at n=8A372126