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%I #26 Jan 02 2016 04:33:12
%S 9,21,25,27,33,35,39,45,49,50,51,55,57,63,65,69,70,75,77,81,85,87,91,
%T 93,95,98,99,105,110,111,115,117,119,121,123,125
%N Numbers n such that the symmetric representation of sigma(n) has at least two parts of distinct size.
%C In other words: numbers n such that the symmetric representation of sigma(n) has at least two parts with distinct number of cells.
%C For more information about the symmetric representation of sigma see A237270 and A237593.
%e The symmetric representation of sigma(9) = 13 in the first quadrant looks like this:
%e y
%e .
%e ._ _ _ _ _ 5
%e |_ _ _ _ _|
%e . |_ _ 3
%e . |_ |
%e . |_|_ _ 5
%e . | |
%e . | |
%e . | |
%e . | |
%e . . . . . . . . |_| . . x
%e .
%e There are three parts: 5 + 3 + 5 = 13, so 9 is in the sequence because the structure contains at least two parts of distinct size.
%Y Complement of A265999.
%Y Cf. A000203, A196020, A235791, A236104, A237270, A237271, A237591, A237593, A239660, A239931-A239934, A245092, A262626.
%K nonn,more
%O 1,1
%A _Omar E. Pol_, Dec 19 2015
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