A278447 -id:A278447

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A279160

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

+10
1

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

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

EXAMPLE

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.

KEYWORD

nonn,tabf,more

AUTHOR

Omar E. Pol, Dec 07 2016

STATUS

approved

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