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.

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

Author

Omar E. Pol, Nov 09 2017

Keywords

• nonn
• more

Examples

			Illustration of initial terms (n = 1..6):
.                                                      _ _ _ _
.                                        _ _ _         _ _ _  |_
.                            _ _ _       _ _ _|        _ _ _|   |_
.                  _ _       _ _  |_     _ _  |_ _     _ _  |_ _  |
.          _ _     _ _|_     _ _|_  |    _ _|_  | |    _ _|_  | | |
.    _     _  |    _  | |    _  | | |    _  | | | |    _  | | | | |
.     |     | |     | | |     | | | |     | | | | |     | | | | | |
.
.    2      4        6          10           12             18
.
		

Crossrefs

Cf. A000203, A024916, A196020, A235791, A236104, A237048, A237270, A237271, A237590, A237591, A237593, A245092, A262626, A294723, A294847.

Formula

a(n) = A294847(n) - 2.