A294849 - OEIS

%I #18 Jul 26 2018 07:05:39

%S 0,1,2,3,5,6,9,10,13,15,18,19,23,24,27,31,36,37,42,43,48,52,55,56,62,

%T 65,68,72,79,80

%N a(n) is the total number of horizontal line segments that belong to the Dyck paths in the diagram of the symmetries of sigma described in A236104 and A237593 after n-th stage, with a(0) = 0.

%C Since the diagram is symmetrics a(n) is also the number of vertical line segments after n-th stage. For a diagram see A293750.

%F a(n) = A293750(n)/2.

%Y Cf. A000203, A196020, A235791, A236104, A237048, A237591, A237593, A245092, A293750, A294847, A294848.

%K nonn,more

%O 0,3

%A _Omar E. Pol_, Nov 09 2017