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A039957 Square-free numbers congruent to 3 mod 4. +0
8
3, 7, 11, 15, 19, 23, 31, 35, 39, 43, 47, 51, 55, 59, 67, 71, 79, 83, 87, 91, 95, 103, 107, 111, 115, 119, 123, 127, 131, 139, 143, 151, 155, 159, 163, 167, 179, 183, 187, 191, 195, 199, 203, 211, 215, 219, 223, 227, 231, 235, 239, 247, 251, 255 (list; graph; listen)
OFFSET

0,1

COMMENT

Negative of odd fundamental discriminants D := b^2-4*a*c<0 of definite integer binary quadratic forms F=a*x^2+b*x*y+c*y^2. See Buell reference pp. 224-230. See 4*A089269 for the even case and A003657 for combined even and odd numbers. - Wolfdieter Lang, Nov 07 2003

REFERENCES

R. A. Mollin, Quadratics, CRC Press, 1996, Tables B1-B3.

D. A. Buell, Binary Quadratic Forms. Springer-Verlag, NY, 1989.

CROSSREFS

Cf. A039955, A039956.

Sequence in context: A004767 A131098 A118894 this_sequence A079422 A022797 A109507

Adjacent sequences: A039954 A039955 A039956 this_sequence A039958 A039959 A039960

KEYWORD

nonn,easy,nice

AUTHOR

R. K. Guy (rkg(AT)cpsc.ucalgary.ca)

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Last modified December 13 23:45 EST 2009. Contains 170824 sequences.


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