This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A318520 Number of unlabeled rooted identity trees with n non-binary nodes. 2
 0, 1, 1, 1, 1, 1, 1, 2, 3, 5, 8, 14, 23, 40, 69, 122, 215, 382, 679, 1217, 2185, 3944, 7136, 12958, 23578, 43026, 78673, 144190, 264755, 487074, 897549, 1656697, 3062423, 5669110, 10508397, 19503447, 36240898, 67418514, 125551221, 234047825, 436722486 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,8 LINKS Alois P. Heinz, Table of n, a(n) for n = 0..3501 EXAMPLE a(8) = 3:    o      o        o              |      |       /|\              o      o      o o o              |     /|\     | |              o    o o o    o o              |    | |      |              o    o o      o              |    |        |              o    o        o              |              o              |              o              |              o MAPLE b:= proc(n, i, t) option remember; `if`(n=0, `if`(t=1, 0, 1), `if`(i<1, 0,       add(b(n-i*j, i-1, max(0, t-j))*binomial(a(i), j), j=0..n/i)))     end: a:= n-> `if`(n<2, n, b(n-1\$2, 3)): seq(a(n), n=0..50); CROSSREFS Cf. A000081, A004111, A303023. Sequence in context: A000621 A191317 A218020 * A039828 A246360 A005627 Adjacent sequences:  A318517 A318518 A318519 * A318521 A318522 A318523 KEYWORD nonn AUTHOR Alois P. Heinz, Aug 28 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 | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 9 00:32 EST 2019. Contains 329871 sequences. (Running on oeis4.)