A279160 Irregular triangle read by rows in which row n lists the perimeters of the parts of the symmetric representation of sigma(n).

4, 8, 6, 6, 16, 8, 8, 24, 10, 10, 32, 12, 8, 12, 20, 20, 14, 14, 48, 16, 16, 26, 26, 18, 16, 18, 64

Offset

1,1

Links

Table of n, a(n) for n=1..27.

Example

4;
8;
6, 6;
16;
8, 8;
24;
10, 10;
32;
12, 8, 12;
20, 20;
14, 14;
48;
16, 16;
26, 26;
18, 16, 18;
64;
...
Illustration of the 9th row:
.         12
.     _ _ _ _ _
.    |_ _ _ _ _|
.               _ _ 8
.              |_  |
.                |_|  _
.                    | |
.                    | |
.                    | |  12
.                    | |
.                    |_|
.
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 as shown above, so the 9th row of triangle is 12, 8, 12.

Crossrefs

Twice A278447.

Row sums give A274919.

Cf. A237271 gives the row lengths.

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

Sequence in context: A201527 A063808 A081455 * A197290 A200368 A322087

Adjacent sequences: A279157 A279158 A279159 * A279161 A279162 A279163

Keyword

nonn,tabf,more

Author

Omar E. Pol, Dec 07 2016

Status

approved