A237610 Positive integers k such that x^2 - 10xy + y^2 + k = 0 has integer solutions.

8, 15, 20, 23, 24, 32, 47, 60, 71, 72, 80, 87, 92, 95, 96, 116, 128, 135, 152, 159, 167, 180, 188, 191, 200, 207, 212, 215, 216, 239, 240, 263, 276, 284, 288, 303, 311, 320, 335, 344, 348, 359, 368, 375, 380, 383, 384, 392, 404, 423, 431, 447, 456, 464, 479

Offset

1,1

Links

Table of n, a(n) for n=1..55.

Example

15 is in the sequence because x^2 - 10xy + y^2 + 15 = 0 has integer solutions, for example (x, y) = (2, 19).

Prog

(PARI) is(n)=m=bnfisintnorm(bnfinit(x^2-10*x+1), -n); #m>0&&denominator(polcoeff(m[1], 1))==1 \\ Ralf Stephan, Feb 11 2014

Crossrefs

Cf. A072256 (k = 8), A129445 (k = 15), A080806 (k = 20), A074061 (k = 23), A001079 (k = 24).

Cf. A031363, A084917, A237351, A237599, A237606, A237609.

Sequence in context: A247081 A133157 A014544 * A122754 A355490 A082867

Adjacent sequences: A237607 A237608 A237609 * A237611 A237612 A237613

Keyword

nonn

Author

Colin Barker, Feb 10 2014

Status

approved