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A254063 Positive integers whose square is expressible in exactly one way as x^2 + 5xy + y^2, with 0 < x < y. 4
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 (list; graph; refs; listen; history; text; internal format)
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: A236844 A271468 A313669 * A313670 A321513 A188043

Adjacent sequences:  A254060 A254061 A254062 * A254064 A254065 A254066

KEYWORD

nonn

AUTHOR

Colin Barker, Jan 24 2015

STATUS

approved

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Last modified December 12 22:06 EST 2019. Contains 329963 sequences. (Running on oeis4.)