Squares that remain squares if prefixed with a 1.

Terms

a(0) =225a(1) =5625a(2) =22500a(3) =562500a(4) =2250000a(5) =5405625a(6) =23765625a(7) =56250000a(8) =225000000a(9) =540562500a(10) =2127515625a(11) =2376562500a(12) =5625000000a(13) =22500000000a(14) =54056250000a(15) =58503515625a(16) =212751562500a(17) =237656250000a(18) =562500000000