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Irregular triangle read by rows in which row n lists the semiperimeters of the parts of the symmetric representation of sigma(n).
1

%I #24 Dec 11 2016 00:23:46

%S 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

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

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

%e Triangle begins:

%e 2;

%e 4;

%e 3, 3;

%e 8;

%e 4, 4;

%e 12;

%e 5, 5;

%e 16;

%e 6, 4, 6;

%e 10, 10;

%e 7, 7;

%e 24;

%e 8, 8;

%e 13, 13;

%e 9, 8, 9;

%e 32;

%e ...

%e 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.

%Y Row sums give A244363.

%Y Cf. A237271 gives the row lengths.

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

%K nonn,tabf,more

%O 1,1

%A _Omar E. Pol_, Dec 07 2016