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 A190317 Number of acute isosceles triangles on a (n X n)-grid. 4
 0, 0, 8, 48, 164, 448, 976, 1864, 3328, 5512, 8640, 12984, 18836, 26576, 36584, 49056, 64560, 83640, 106904, 134816, 168004, 206952, 252480, 305360, 366312, 436120, 515864, 605928, 707644, 822120, 950216, 1092784, 1251784, 1427848, 1622416, 1835968, 2070404 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Place all bounding boxes of A279418 that will fit into the n X n grid in all possible positions, and the proper rectangles in two orientations: a(n) = Sum(i=1..n, Sum(j=1..i, k * (n-i+1) * (n-j+1) * A279418(i,j))) where k=1 when i=j and k=2 otherwise. - Lars Blomberg, Mar 02 2017 LINKS Lars Blomberg, Table of n, a(n) for n = 1..10000 (the first 100 terms from Chai Wah Wu) FORMULA a(n) = A186434(n) - A187452(n) - A190318(n) CROSSREFS Cf. A186434, A187452, A190318, A279418. Sequence in context: A035471 A209443 A072819 * A073912 A212571 A247727 Adjacent sequences:  A190314 A190315 A190316 * A190318 A190319 A190320 KEYWORD nonn AUTHOR Martin Renner, May 08 2011 EXTENSIONS a(10)-a(37) from Nathaniel Johnston, May 09 2011 STATUS approved

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Last modified January 23 22:26 EST 2019. Contains 319404 sequences. (Running on oeis4.)