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A028955 Numbers represented by quadratic form with Gram matrix [ 4, 1; 1, 4 ] (divided by 2). +0
4
0, 2, 3, 5, 8, 12, 17, 18, 20, 23, 27, 30, 32, 38, 45, 47, 48, 50, 53, 57, 62, 68, 72, 75, 80, 83, 92, 93, 95, 98, 102, 107, 108, 113, 120, 122, 125, 128, 137, 138, 147, 152, 153, 155, 158, 162, 167, 170, 173, 180, 183, 188, 192, 197, 200, 207, 212, 218, 227, 228 (list; graph; listen)
OFFSET

1,2

FORMULA

a(x, y) = (4x^2 + 2xy + 4y^2)/2; x, y any integer.

CROSSREFS

Cf. A028927.

Adjacent sequences: A028952 A028953 A028954 this_sequence A028956 A028957 A028958

Sequence in context: A062489 A084624 A004170 this_sequence A104664 A022856 A089071

KEYWORD

nonn,easy

AUTHOR

njas

EXTENSIONS

More terms from Larry Reeves (larryr(AT)acm.org), Mar 29 2000

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Last modified October 11 13:47 EDT 2008. Contains 144830 sequences.


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