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a(n) is the total length of all line segments in an octant of the symmetric representation of sigma(n).
2

%I #21 Dec 19 2021 15:58:59

%S 2,4,6,8,9,12,12,16,17,20,18,24,21,27,28,32,27,36,30,40,39,41,36,48,

%T 42,48,49,56,45,60,48,64

%N a(n) is the total length of all line segments in an octant of the symmetric representation of sigma(n).

%C One half of the total length of all line segments of the symmetric representation of sigma(n).

%C If the symmetric representation of sigma(n) has only one part (cf. A174973) or if it has two parts and they meet at the center of the Dyck path (cf. A262259) then a(n) = 2*n, otherwise a(n) < 2*n. In other words: if n is a term of A279029 then a(n) = 2*n, otherwise a(n) < 2*n.

%F a(n) = A348705(n)/2.

%Y Cf. A005843 (upper bounds).

%Y For illustrations see A348705.

%Y Cf. A174973, A235791, A236104, A237270, A237271, A237591, A237593, A238443, A239660, A239931-A239934, A245092, A262259, A279029.

%K nonn,more

%O 1,1

%A _Omar E. Pol_, Nov 01 2021