a(n) = A000172(n)^2.A052144a(n) = A000172(n)^2.Terms a(0) =1a(1) =4a(2) =100a(3) =3136a(4) =119716a(5) =5071504a(6) =230553856a(7) =11016601600a(8) =546360462244External referencesoeis: A052144