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%I #41 Jul 31 2018 09:57:41
%S 0,4,8,14,20,26,36,42,50,60,70,76,92,98,108,124,136,142,160,166,182,
%T 198,208,214,238,250,260,276,294,300
%N a(n) is the total number of edges after n-th stage in the diagram of the symmetries of sigma in which the parts of width > 1 are dissected into subparts of width 1, with a(0) = 0.
%C All terms are even numbers.
%C Note that in the diagram the number of regions or subparts equals A060831, the partial sums of A001227, n >= 1.
%F a(n) = A317293(n) + A060831(n) - 1 (Euler's formula).
%e Illustration of initial terms (n = 1..9):
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%e Illustration of the two-dimensional diagram after 29 stages (contains 300 edges, 239 vertices and 62 regions or subparts):
%e ._ _ _ _ _ _ _ _ _ _ _ _ _ _ _
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%e .
%Y For the definition of "subparts" see A279387.
%Y For the triangle of sums of subparts see A279388.
%Y Cf. A317293 (number of vertices).
%Y Cf. A060831 (number of regions or subparts).
%Y Compare with A317109 (analog for the diagram that contains only parts).
%Y First differs from A317109 at a(6).
%Y Cf. A000203, A001227, A196020, A235791, A237048, A237590, A237591, A237270, A237271, A237593, A245092, A244050, A262626, A280850, A280851, A280940, A285901, A294723, A296508.
%K nonn,more
%O 0,2
%A _Omar E. Pol_, Jul 27 2018