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A293750
a(n) is the total number of 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.
2
0, 2, 4, 6, 10, 12, 18, 20, 26, 30, 36, 38, 46, 48, 54, 62, 72, 74, 84, 86, 96, 104, 110, 112, 124, 130, 136, 144, 158, 160
OFFSET
0,2
FORMULA
a(n) = A294847(n) - 2.
EXAMPLE
Illustration of initial terms (n = 1..6):
. _ _ _ _
. _ _ _ _ _ _ |_
. _ _ _ _ _ _| _ _ _| |_
. _ _ _ _ |_ _ _ |_ _ _ _ |_ _ |
. _ _ _ _|_ _ _|_ | _ _|_ | | _ _|_ | | |
. _ _ | _ | | _ | | | _ | | | | _ | | | | |
. | | | | | | | | | | | | | | | | | | | | |
.
. 2 4 6 10 12 18
.
KEYWORD
nonn,more
AUTHOR
Omar E. Pol, Nov 09 2017
STATUS
approved