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A248599 Positive integers whose square is expressible in exactly one way as x^2 + 4xy + y^2, with 0 < x < y. 4
11, 13, 22, 23, 26, 33, 37, 39, 44, 46, 47, 52, 55, 59, 61, 65, 66, 69, 71, 73, 74, 77, 78, 83, 88, 91, 92, 94, 97, 99, 104, 107, 109, 110, 111, 115, 117, 118, 122, 130, 131, 132, 138, 141, 142, 146, 148, 154, 156, 157, 161, 165, 166, 167, 176, 177, 179, 181 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

EXAMPLE

11 is in the sequence because the only solution to x^2 + 4xy + y^2 = 121 with 0 < x < y is (x,y) = (4,5).

CROSSREFS

Cf. A232437, A084645, A254063, A254064.

Sequence in context: A235479 A089774 A257864 * A274243 A192931 A002367

Adjacent sequences:  A248596 A248597 A248598 * A248600 A248601 A248602

KEYWORD

nonn

AUTHOR

Colin Barker, Jan 21 2015

STATUS

approved

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Last modified December 13 06:26 EST 2019. Contains 329968 sequences. (Running on oeis4.)