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A278447
Irregular triangle read by rows in which row n lists the semiperimeters of the parts of the symmetric representation of sigma(n).
1
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
OFFSET
1,1
FORMULA
a(n) = A279160(n)/2.
EXAMPLE
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 perĂ­meters of the parts are 12, 8 and 12, so the 9th row of triangle lists the semiperimeters: 6, 4, 6.
CROSSREFS
Row sums give A244363.
Cf. A237271 gives the row lengths.
Sequence in context: A303354 A330256 A227418 * A235590 A069655 A353706
KEYWORD
nonn,tabf,more
AUTHOR
Omar E. Pol, Dec 07 2016
STATUS
approved