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

1,1

LINKS

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

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.

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

Sequence in context: A201049 A303354 A227418 * A235590 A069655 A004574

Adjacent sequences:  A278444 A278445 A278446 * A278448 A278449 A278450

KEYWORD

nonn,tabf,more

AUTHOR

Omar E. Pol, Dec 07 2016

STATUS

approved

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Last modified October 17 14:47 EDT 2019. Contains 328114 sequences. (Running on oeis4.)