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Search: id:A062684
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| A062684 |
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Number of addition triangles with apex n (version 1). |
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+0
3
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| 1, 2, 3, 5, 7, 10, 13, 18, 23, 29, 37, 46, 55, 68, 81, 96, 115, 135, 155, 183, 211, 241, 277, 317, 357, 407, 457, 513, 577, 645, 713, 799, 885, 977, 1079, 1191, 1305, 1438, 1571, 1717, 1875, 2048, 2221, 2423, 2625, 2840, 3077, 3333, 3589, 3876, 4163
(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 counts as a different triangle.
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EXAMPLE
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For n = 5:
..5.......5.................................
.2,3.....3,2.....5.....5.....5.....5........
1,1,2...2,1,1...4,1...1,4...2,3...3,2...5...
with seven different bases, so a(5) = 7.
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CROSSREFS
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Cf. A028307, A066411, see A062896 for version 2.
Sequence in context: A115001 A008766 A103232 this_sequence A033485 A026811 A001401
Adjacent sequences: A062681 A062682 A062683 this_sequence A062685 A062686 A062687
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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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