Numbers k such that the concatenation of k with 8*k gives a square.

Terms

a(0) =3a(1) =12a(2) =28a(3) =63a(4) =112a(5) =278a(6) =1112a(7) =2778a(8) =11112a(9) =27778a(10) =111112a(11) =277778a(12) =1111112a(13) =2777778a(14) =4938272a(15) =7716050a(16) =11111112a(17) =12802888a(18) =13151250a(19) =13504288a(20) =13862002a(21) =14224392a(22) =14591458a(23) =14963200a(24) =15339618a(25) =15720712a(26) =16106482a(27) =16496928a(28) =16892050a(29) =17291848