A241227 - OEIS

A241227

Number of scalene triangles on a centered hexagonal grid of size n.

0, 12, 648, 6084, 30444, 107376, 302916, 732024, 1576728, 3111012, 5724852, 9952620, 16509336, 26321160, 40567872, 60724104, 88605480, 126413772, 176788476, 242874756, 328359624, 437553360

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OFFSET

1,2

COMMENTS

A centered hexagonal grid of size n is a grid with A003215(n-1) points forming a hexagonal lattice.

LINKS

Table of n, a(n) for n=1..22.

Eric Weisstein's World of Mathematics, Hex Number.

Eric Weisstein's World of Mathematics, Scalene Triangle.

FORMULA

a(n) = A241223(n) - A241228(n).

CROSSREFS

Cf. A190312.

Sequence in context: A013587 A126159 A220992 * A268549 A071307 A195574

Adjacent sequences: A241224 A241225 A241226 * A241228 A241229 A241230

KEYWORD

nonn,more

AUTHOR

Martin Renner, Apr 17 2014

EXTENSIONS

a(7) from Martin Renner, May 31 2014

a(8)-a(22) from Giovanni Resta, May 31 2014

STATUS

approved