This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A028419 Congruence classes of triangles which can be drawn using lattice points in n X n grid as vertices. 11
 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, 485427, 535049, 588457, 645803 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Ron Knott, Table of n, a(n) for n = 0..60 D. Rusin, Lattice Problem (Triangles) [Dead link] D. Rusin, Lattice Problem (Triangles) [Cached copy] 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, May 03 2011 CROSSREFS Cf. A028492, A189979, A190021, A190022, A189978, A190313, A189978, A190313. Sequence in context: A106113 A299260 A290312 * A046664 A055536 A131438 Adjacent sequences:  A028416 A028417 A028418 * A028420 A028421 A028422 KEYWORD nonn AUTHOR EXTENSIONS More terms from Chris Cole (chris(AT)questrel.com), Jun 28 2003 a(36)-a(39) from Martin Renner, May 08 2011 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 15 19:25 EDT 2019. Contains 328037 sequences. (Running on oeis4.)