The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A301750 Number of rooted twice-partitions of n where the composite rooted partition is strict. 3
 1, 1, 2, 3, 5, 8, 12, 18, 29, 42, 61, 86, 127, 181, 257, 352, 489, 668, 935, 1270, 1730, 2312, 3101, 4112, 5533, 7345, 9742, 12785, 16793, 21821, 28452, 36908, 48108, 62198, 80337, 103081, 132372, 168805, 215247, 273678 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS A rooted partition of n is an integer partition of n - 1. A rooted twice-partition of n is a choice of a rooted partition of each part in a rooted partition of n. LINKS EXAMPLE The a(8) = 18 rooted twice-partitions where the composite rooted partition is strict: (6), (51), (42), (321), (5)(), (41)(), (32)(), (4)(1), (3)(2), (4)()(), (31)()(), (3)(1)(), (3)()()(), (21)()()(), (2)(1)()(), (2)()()()(), (1)()()()()(), ()()()()()()(). MATHEMATICA twirtns[n_]:=Join@@Table[Tuples[IntegerPartitions[#-1]&/@ptn], {ptn, IntegerPartitions[n-1]}]; Table[Select[twirtns[n], UnsameQ@@Join@@#&]//Length, {n, 30}] CROSSREFS Cf. A002865, A063834, A093637, A127524, A279790, A294788, A301422, A301462, A301467, A301480, A301706. Sequence in context: A130732 A018135 A065435 * A086676 A055804 A267372 Adjacent sequences:  A301747 A301748 A301749 * A301751 A301752 A301753 KEYWORD nonn AUTHOR Gus Wiseman, Mar 26 2018 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 18 09:01 EDT 2022. Contains 356204 sequences. (Running on oeis4.)