A338740 Number of hairpin compositions of n.

0, 0, 0, 0, 2, 4, 14, 28, 70, 140, 310, 621, 1302, 2607, 5335, 10675, 21593

Offset: 1

Author

Michel Marcus, Nov 06 2020

Keywords

• nonn
• base
• more

Comments

A hairpin composition with t parts is a composition that is true-palindromic except for a part-sequence in the center of length at least 1 but no more than t-2. [Shapcott p. 46]

Links

• Caroline Shapcott, An introduction to true-palindromic compositions, Australasian Journal of Combinatorics, Volume 60(1) (2014), Pages 35-49.

Crossrefs

Cf. A002113, A004086, A056964.

Cf. A016116 (symmetric compositions), A338739.