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A028419
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Congruence classes of triangles which can be drawn using lattice points in n X n grid as vertices.
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9
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0, 1, 8, 29, 79, 172, 333, 587, 963, 1494, 2228, 3195, 4455, 6050, 8032, 10481, 13464, 17014, 21235, 26190, 31980, 38666, 46388, 55144, 65131, 76449, 89132, 103337, 119184, 136757, 156280, 177796, 201430, 227331, 255668, 286606, 320294, 356884, 396376, 439100
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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LINKS
| D. Rusin, Lattice Problem (Triangles)
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MAPLE
| a:=proc(n) local TriangleSet, i, j, k, l, A, B, C; TriangleSet:={}: for i from 0 to n do for j from 0 to n do for k from 0 to n do for l from 0 to n do A:=i^2+j^2: B:=k^2+l^2: C:=(i-k)^2+(j-l)^2: if A^2+B^2+C^2<>2*(A*B+B*C+C*A) then TriangleSet:={op(TriangleSet), sort([sqrt(A), sqrt(B), sqrt(C)])}: fi: od: od: od: od: return(nops(TriangleSet)); end: # Martin Renner (martin.renner(AT)gmx.net), May 03 2011
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CROSSREFS
| Cf. A028492, A189979, A190021, A190022.
Sequence in context: A037157 A100178 A106113 * A046664 A055536 A131438
Adjacent sequences: A028416 A028417 A028418 * A028420 A028421 A028422
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KEYWORD
| nonn
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AUTHOR
| Dave Rusin (rusin(AT)math.niu.edu)
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EXTENSIONS
| More terms from Chris Cole (chris(AT)questrel.com), Jun 28 2003
a(36)-a(39) from Martin Renner (martin.renner(AT)gmx.net), May 08 2011
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