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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, 33021, 44272, 58180, 75148, 95526, 119758, 148489, 181924, 220796, 265519, 316736, 375006, 441061, 515467, 598680, 691761, 795410, 909971, 1036745, 1176108, 1329286, 1496711, 1679852, 1879036, 2095235
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
Sequence in context: A086120 A129701 A221746 * A044270 A044651 A287303
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
More terms from Bert Dobbelaere, Oct 17 2022
STATUS
approved