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A338740
Number of hairpin compositions of n.
1
0, 0, 0, 0, 2, 4, 14, 28, 70, 140, 310, 621, 1302, 2607, 5335, 10675, 21593
OFFSET
1,5
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. A016116 (symmetric compositions), A338739.
Sequence in context: A288154 A283353 A323656 * A365544 A360791 A304341
KEYWORD
nonn,base,more
AUTHOR
Michel Marcus, Nov 06 2020
STATUS
approved