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A062896
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Number of addition triangles with apex n (version 2).
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2
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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; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| 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
| 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
| Cf. A028307, A066411, see A062684 for version 1.
Sequence in context: A099383 A197122 A064410 * A025065 A131524 A089075
Adjacent sequences: A062893 A062894 A062895 * A062897 A062898 A062899
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KEYWORD
| easy,nonn
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AUTHOR
| Naohiro Nomoto (n_nomoto(AT)yabumi.com), Feb 11 2002
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EXTENSIONS
| Extended and edited by John W. Layman (layman(AT)math.vt.edu), Feb 14 2002
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