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Search: id:A116513
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| A116513 |
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Number of distinct hexagons of n points chosen from triangular lattice A_2 with sides parallel to the principal axes of that lattice. Degenerate sides (of length 1) are permitted. |
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+0
1
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| 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 3, 5, 4, 5, 6, 5, 4, 7, 6, 6, 7, 6, 6, 9, 7, 7, 8, 8, 8, 10, 6, 8, 11, 10, 9, 12
(list; graph; listen)
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OFFSET
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1,3
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COMMENT
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This sequence is to the lattice A2 as sequence A038548 is to the lattice D2; presumably other lattices have analogous sequences.
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EXAMPLE
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a(7) = 3 because (reading the rows of the hexagons) 7 = 3+4 = 2+3+2.
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CROSSREFS
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Cf. A038548.
Sequence in context: A112754 A045864 A072302 this_sequence A122651 A130535 A026819
Adjacent sequences: A116510 A116511 A116512 this_sequence A116514 A116515 A116516
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KEYWORD
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more,nonn
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AUTHOR
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Allan C. Wechsler (acwacw(AT)gmail.com), Mar 23 2006
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EXTENSIONS
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More terms up to n=32 from Allan C. Wechsler (acwacw(AT)gmail.com), Mar 31 2006
Corrected and extended to n=36 by Allan C. Wechsler (acwacw(AT)gmail.com), Feb 15 2008
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