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 A241236 Number of scalene triangles, distinct up to congruence, on a centered hexagonal grid of size n. 2
 0, 1, 19, 99, 310, 760, 1556, 2863, 4849, 7713, 11702, 17077, 24066 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS A centered hexagonal grid of size n is a grid with A003215(n-1) points forming a hexagonal lattice. LINKS Eric Weisstein's World of Mathematics, Hex Number. Eric Weisstein's World of Mathematics, Scalene Triangle. FORMULA a(n) = A241231(n) - A241237(n). EXAMPLE For n = 2 the only kind of non-congruent scalene triangles is the following: /. * * . * \. . CROSSREFS Cf. A190313, A241227. Sequence in context: A086120 A129701 A221746 * A044270 A044651 A287303 Adjacent sequences:  A241233 A241234 A241235 * A241237 A241238 A241239 KEYWORD nonn AUTHOR Martin Renner, Apr 17 2014 EXTENSIONS a(7) from Martin Renner, May 31 2014 a(8)-a(13) from Giovanni Resta, May 31 2014 STATUS approved

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Last modified February 19 09:57 EST 2020. Contains 332041 sequences. (Running on oeis4.)