a(n) is the smallest nonnegative integer k such that n + k and n*k are squares, or -1 if there is no such number.

A383898

a(n) is the smallest nonnegative integer k such that n + k and n*k are squares, or -1 if there is no such number.

Terms

    a(0) =0a(1) =2a(2) =-1a(3) =0a(4) =20a(5) =-1a(6) =-1a(7) =8a(8) =0a(9) =90a(10) =-1a(11) =-1a(12) =4212a(13) =-1a(14) =-1a(15) =0a(16) =272a(17) =18a(18) =-1a(19) =5a(20) =-1a(21) =-1a(22) =-1a(23) =-1a(24) =0a(25) =650a(26) =-1a(27) =-1a(28) =142100a(29) =-1

External references