Least k such that n! + k^2 is a square.

Terms

a(0) =1a(1) =1a(2) =3a(3) =1a(4) =9a(5) =27a(6) =15a(7) =18a(8) =288a(9) =288a(10) =420a(11) =464a(12) =1856a(13) =10080a(14) =46848a(15) =210240a(16) =400320a(17) =652848a(18) =3991680a(19) =27528402a(20) =32659200a(21) =163296000a(22) =1143463200a(23) =1305467240a(24) =6840489600a(25) =9453465438a(26) =337082683248a(27) =163425485250