OFFSET
0,4
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..1000
EXAMPLE
The a(1) = 1 through a(7) = 13 compositions:
(1) (2) (3) (4) (5) (6) (7)
(12) (13) (14) (15) (16)
(21) (31) (23) (24) (25)
(211) (32) (42) (34)
(41) (51) (43)
(122) (411) (52)
(311) (1221) (61)
(2112) (133)
(322)
(511)
(2113)
(3112)
(12211)
MATHEMATICA
Table[Length[Select[Join@@Permutations/@IntegerPartitions[n], And@@Table[#[[i]]==#[[i+1]], {i, 2, Length[#]-1, 2}]&&And@@Table[#[[i]]!=#[[i+1]], {i, 1, Length[#]-1, 2}]&]], {n, 0, 10}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Oct 14 2022
EXTENSIONS
More terms from Alois P. Heinz, Oct 19 2022
STATUS
approved