Numbers k such that the decimal number concat(4,k) is a square.

Terms

a(0) =9a(1) =41a(2) =84a(3) =225a(4) =356a(5) =489a(6) =624a(7) =761a(8) =900a(9) =1209a(10) =1616a(11) =2025a(12) =2436a(13) =2849a(14) =3264a(15) =3681a(16) =4100a(17) =4521a(18) =4944a(19) =5369a(20) =5796a(21) =6225a(22) =6656a(23) =7089a(24) =7524a(25) =7961a(26) =8400a(27) =8841a(28) =9284a(29) =9729