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A053457 Open disk numbers (version 2): a(n)= number of points (i,j), i,j, integers, contained in a open disk of diameter n, centered at (0,1/2). 0
0, 0, 2, 6, 12, 16, 26, 38, 48, 60, 78, 94, 108, 128, 154, 174, 196, 224, 250, 278, 312, 344, 378, 410, 452, 484, 526, 574, 612, 652, 698, 754, 800, 848, 906, 958, 1012, 1068, 1130, 1190, 1252, 1316, 1378, 1446, 1516, 1588, 1654, 1730, 1808, 1880, 1954 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

a(n)/(n/2)^2->Pi

LINKS

Table of n, a(n) for n=0..50.

CROSSREFS

A053414, A053456-A053459.

Sequence in context: A088915 A084790 A130237 * A299112 A154030 A055560

Adjacent sequences:  A053454 A053455 A053456 * A053458 A053459 A053460

KEYWORD

easy,nonn

AUTHOR

Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de), Jan 13 2000

STATUS

approved

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Last modified November 30 17:12 EST 2021. Contains 349424 sequences. (Running on oeis4.)