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 A279418 Triangle read by rows: T(n,k), n>=k>=1, is the number of acute isosceles triangles with integer coordinates that have a bounding box of size n X k. 9
 0, 0, 0, 0, 0, 8, 0, 0, 2, 8, 0, 0, 2, 2, 16, 0, 0, 2, 4, 6, 16, 0, 0, 2, 0, 4, 2, 24, 0, 0, 2, 0, 2, 4, 6, 24, 0, 0, 2, 0, 6, 6, 4, 6, 40, 0, 0, 2, 0, 2, 0, 6, 4, 6, 40, 0, 0, 2, 0, 2, 0, 8, 2, 8, 2, 40, 0, 0, 2, 0, 2, 4, 2, 8, 2, 4, 10, 40, 0, 0, 2, 0, 2, 0 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,6 LINKS Lars Blomberg, Table of n, a(n) for n = 1..9870 (the first 140 rows) EXAMPLE Triangle begins: 0 0,0 0,0,8 0,0,2,8 0,0,2,2,16 0,0,2,4,6,16 0,0,2,0,4,2,24 0,0,2,0,2,4,6,24 0,0,2,0,6,6,4,6,40 0,0,2,0,2,0,6,4,6,40 0,0,2,0,2,0,8,2,8,2,40 0,0,2,0,2,4,2,8,2,4,10,40 0,0,2,0,2,0,2,2,8,10,8,10,48 0,0,2,0,2,4,2,4,10,0,2,8,14,48 0,0,2,0,2,0,6,0,4,6,12,6,8,6,56 0,0,2,0,2,0,2,0,2,8,2,0,6,8,10,56 ------ The vertex between the two equal sides is 'o'. For n=3, k=3: x.x   x..   o..   .x.   .x.   .o.   ..o   ..x ...   ..o   ..x   x..   ..x   ...   x..   o.. .o.   x..   .x.   ..o   o..   x.x   .x.   ..x So T(3,3)=8 ------ For n=6, k=4: x....o   o....x   .x....   ....x. ......   ......   ......   ...... ......   ......   ......   ...... .x....   ....x.   x....o   o....x So T(6,4)=4 CROSSREFS Cf. A190317. See A279415 for right isosceles triangles. See A280639 for obtuse isosceles triangles. See A279413 for all isosceles triangles. See A279433 for all right triangles. See A280652 for all obtuse triangles. See A280653 for all acute triangles. See A279432 for all triangles. Sequence in context: A186980 A171918 A265117 * A157244 A154191 A010771 Adjacent sequences:  A279415 A279416 A279417 * A279419 A279420 A279421 KEYWORD nonn,tabl AUTHOR Lars Blomberg, Feb 27 2017 STATUS approved

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Last modified September 21 00:17 EDT 2019. Contains 327252 sequences. (Running on oeis4.)