1/2 the number of n X n arrays of squares of integers with every 2X2 subblock summing to 20.

A159221

1/2 the number of n X n arrays of squares of integers with every 2X2 subblock summing to 20.

Terms

    a(0) =9a(1) =23a(2) =49a(3) =101a(4) =201a(5) =401a(6) =793a(7) =1577a(8) =3129a(9) =6233a(10) =12409a(11) =24761a(12) =49401a(13) =98681a(14) =197113a(15) =393977a(16) =787449a(17) =1574393a(18) =3147769a(19) =6294521a(20) =12587001a(21) =25171961a(22) =50339833a(23) =100675577a(24) =201342969a(25) =402677753a(26) =805339129

External references