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A276456
Integers n such that the Klein invariant J((-1+sqrt(-n))/2) is a rational number.
0
1, 3, 7, 11, 19, 27, 43, 67, 163
OFFSET
1,2
COMMENTS
Probably sequence is finite and complete.
This sequence looks very much like A003173, the Heegner numbers, except for two terms (add 2, remove 27). Is there a proof of this connection? - Luc Rousseau, Nov 30 2017
EXAMPLE
a(1) = 1 because J((-1+sqrt(-1))/2) = 1;
a(2) = 3 because J((-1+sqrt(-3))/2) = 0;
a(3) = 7 because J((-1+sqrt(-7))/2) = -125/64;
a(4) = 11 because J((-1+sqrt(-11))/2) = -512/27;
a(5) = 19 because J((-1+sqrt(-19))/2) = -512;
a(6) = 27 because J((-1+sqrt(-27))/2) = -64000/9;
a(7) = 43 because J((-1+sqrt(-43))/2) = -512000;
a(8) = 67 because J((-1+sqrt(-67))/2) = -85184000;
a(9) = 163 because J((-1+sqrt(-163))/2) = -151931373056000.
CROSSREFS
Sequence in context: A292095 A265323 A346912 * A126254 A092102 A158722
KEYWORD
nonn
AUTHOR
Artur Jasinski, Sep 03 2016
STATUS
approved