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Search: id:A062896
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| A062896 |
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Number of addition triangles with apex n (version 2). |
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+0
3
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| 1, 2, 2, 4, 4, 7, 7, 12, 12, 18, 19, 27, 28, 39, 41, 54, 58, 74, 78, 99, 106, 129, 139, 168, 179, 214, 229, 268, 289, 335, 357, 414, 443, 504, 540, 612, 653, 737, 786, 878, 938, 1045, 1111, 1234, 1313, 1444, 1539, 1692, 1795, 1965, 2082, 2273, 2414
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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An addition triangle has any set of positive numbers as base; other rows are formed by adding pairs of adjacent numbers.
Reversing the base does not count as a different triangle.
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EXAMPLE
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For n = 5:
..5...................
.2,3.....5.....5......
1,1,2...4,1...2,3...5.
with four different bases, so a(5) = 4.
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CROSSREFS
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Cf. A028307, A066411, see A062684 for version 1.
Sequence in context: A099770 A099383 A064410 this_sequence A025065 A131524 A089075
Adjacent sequences: A062893 A062894 A062895 this_sequence A062897 A062898 A062899
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KEYWORD
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easy,nonn
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AUTHOR
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Naohiro Nomoto (n_nomoto(AT)yabumi.com), Feb 11 2002
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EXTENSIONS
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Extended and edited by John W. Layman (layman(AT)math.vt.edu), Feb 14 2002
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