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A057656 Number of points (x,y) in square lattice with (x-1/2)^2+y^2 <= n. 2
2, 6, 8, 12, 16, 16, 22, 26, 26, 30, 34, 38, 40, 44, 44, 48, 56, 56, 60, 60, 62, 70, 74, 74, 78, 82, 82, 86, 90, 94, 96, 104, 104, 104, 108, 108, 116, 120, 124, 128, 128, 128, 134, 138, 138, 142, 150, 150, 154, 158, 158, 166, 166, 166, 166, 174 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

REFERENCES

J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 106.

LINKS

Table of n, a(n) for n=0..55.

CROSSREFS

Partial sums of A004020. Cf. A057656, A057961, A057962.

Sequence in context: A304483 A268177 A083769 * A247066 A084724 A283233

Adjacent sequences:  A057653 A057654 A057655 * A057657 A057658 A057659

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Oct 15 2000

STATUS

approved

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Last modified January 21 20:07 EST 2019. Contains 319350 sequences. (Running on oeis4.)