OFFSET
1,5
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..200
FORMULA
EXAMPLE
The a(3) = 1 through a(6) = 7 trees:
((o)) (((o))) (((oo))) ((((oo))))
((o)(o)) (((o)(o)))
((o(o))) (((o(o))))
(o((o))) ((o)((o)))
((((o)))) ((o((o))))
(o(((o))))
(((((o)))))
MATHEMATICA
art[n_]:=If[n==1, {{}}, Join@@Table[Select[Tuples[art/@c], OrderedQ], {c, Join@@Permutations/@IntegerPartitions[n-1]}]];
Table[Length[Select[art[n], Count[#, {}, {0, Infinity}]<Count[#, _[__], {0, Infinity}]&]], {n, 0, 10}]
PROG
(PARI) \\ See A358584 for R(n).
seq(n) = {my(A=R(n)); vector(n, n, vecsum(Vecrev(A[n]/y)[1..(n-1)\2]))} \\ Andrew Howroyd, Dec 30 2022
CROSSREFS
The non-strict version is A358584.
KEYWORD
nonn
AUTHOR
Gus Wiseman, Nov 23 2022
EXTENSIONS
Terms a(19) and beyond from Andrew Howroyd, Dec 30 2022
STATUS
approved