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A278447
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Irregular triangle read by rows in which row n lists the semiperimeters of the parts of the symmetric representation of sigma(n).
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1
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2, 4, 3, 3, 8, 4, 4, 12, 5, 5, 16, 6, 4, 6, 10, 10, 7, 7, 24, 8, 8, 13, 13, 9, 8, 9, 32
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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LINKS
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Table of n, a(n) for n=1..27.
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FORMULA
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a(n) = A279160(n)/2.
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EXAMPLE
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Triangle begins:
2;
4;
3, 3;
8;
4, 4;
12;
5, 5;
16;
6, 4, 6;
10, 10;
7, 7;
24;
8, 8;
13, 13;
9, 8, 9;
32;
...
For n = 9 the symmetric representation of sigma(9) = 13 has three parts of areas 5, 3, 5 respectively. The perímeters of the parts are 12, 8 and 12, so the 9th row of triangle lists the semiperimeters: 6, 4, 6.
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CROSSREFS
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Row sums give A244363.
Cf. A237271 gives the row lengths.
Cf. A000203, A196020, A236104, A235791, A237270, A237591, A237593, A245092, A262626, A279160.
Sequence in context: A303354 A330256 A227418 * A235590 A069655 A004574
Adjacent sequences: A278444 A278445 A278446 * A278448 A278449 A278450
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KEYWORD
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nonn,tabf,more
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AUTHOR
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Omar E. Pol, Dec 07 2016
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STATUS
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approved
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