A254063 Positive integers whose square is expressible in exactly one way as x^2 + 5xy + y^2, with 0 < x < y.

5, 10, 15, 17, 20, 30, 34, 35, 37, 40, 41, 43, 45, 47, 51, 55, 59, 60, 65, 67, 68, 70, 74, 79, 80, 82, 83, 86, 89, 90, 94, 95, 101, 102, 105, 109, 110, 111, 115, 118, 119, 120, 123, 127, 129, 130, 131, 134, 135, 136, 140, 141, 145, 148, 151, 153, 155, 158

Offset

1,1

Links

Colin Barker, Table of n, a(n) for n = 1..750

Example

5 is in the sequence because the only solution to x^2 + 5xy + y^2 = 25 with 0 < x < y is (x,y) = (1,3).

Crossrefs

Cf. A084645, A232437, A248599, A254064.

Sequence in context: A271468 A313669 A353167 * A313670 A321513 A188043

Adjacent sequences: A254060 A254061 A254062 * A254064 A254065 A254066

Keyword

nonn

Author

Colin Barker, Jan 24 2015

Status

approved