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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
OFFSET
1,1
LINKS
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
KEYWORD
nonn
AUTHOR
Colin Barker, Jan 24 2015
STATUS
approved