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URL: https://oeis.org/A190310

⇱ A190310 - OEIS

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A190310
Number of obtuse isosceles triangles, distinct up to congruence, on an n X n grid (or geoboard).
2
0, 0, 0, 1, 3, 5, 9, 12, 19, 24, 32, 37, 51, 57, 69, 80, 99, 107, 127, 136, 161, 176, 196, 207, 246, 262, 286, 306, 343, 357, 399, 414, 460, 485, 517, 544, 605, 623, 659, 689, 757
OFFSET
1,5
LINKS
Eric Weisstein's World of Mathematics, Geoboard.
Eric Weisstein's World of Mathematics, Obtuse Triangle.
Eric Weisstein's World of Mathematics, Isosceles Triangle.
FORMULA
a(n) = A189978(n) - A190309(n) - A108279(n).
CROSSREFS
KEYWORD
nonn
AUTHOR
Martin Renner, May 08 2011
STATUS
approved