A278447 Irregular triangle read by rows in which row n lists the semiperimeters of the parts of the symmetric representation of sigma(n).

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

Author

Omar E. Pol, Dec 07 2016

Keywords

• nonn
• tabf
• more

Examples

			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.
		

Crossrefs

Row sums give A244363.

Cf. A237271 gives the row lengths.

Cf. A000203, A196020, A236104, A235791, A237270, A237591, A237593, A245092, A262626, A279160.

Formula

a(n) = A279160(n)/2.