A105831 For n>2, a(n) not appeared previously is such that a(n-1)^2+4*a(n-2)*a(n) is a minimal square, a(1)=1, a(2)=6.

1, 6, 7, 3, 4, 15, 19, 8, 11, 10, 21, 13, 18, 16, 2, 5, 12, 9, 30, 24, 54, 33, 17, 26, 43, 28, 71, 39, 32, 55, 87, 46, 25, 66, 27, 93, 22, 56, 78, 23, 31, 114, 40, 74, 36, 38, 68, 106, 60, 166, 42, 124, 110, 14, 48, 62, 85, 58, 143, 86, 57, 29, 140, 169, 51, 118, 45, 52, 76, 128