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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A270495 Sum of the sizes of the third blocks in all set partitions of {1,2,...,n}. 2
 1, 8, 47, 253, 1345, 7304, 41193, 243152, 1506521, 9799547, 66844755, 477297022, 3560469469, 27692022408, 224128400923, 1884299045789, 16427961558365, 148293477761232, 1384008870213057, 13336887952918752, 132535336519342301, 1356662080571809755 (list; graph; refs; listen; history; text; internal format)
 OFFSET 3,2 LINKS Alois P. Heinz, Table of n, a(n) for n = 3..575 Wikipedia, Partition of a set MAPLE b:= proc(n, m) option remember; `if`(n=0, [1, 0], add((p->`if`(j<4, [p[1], p[2]+p[1]*x^j], p))( b(n-1, max(m, j))), j=1..m+1)) end: a:= n-> coeff(b(n, 0)[2], x, 3): seq(a(n), n=3..25); MATHEMATICA b[n_, m_] := b[n, m] = If[n == 0, {1, 0}, Sum[Function[p, If[j < 4, {p[[1]], p[[2]] + p[[1]]*x^j}, p]][b[n - 1, Max[m, j]]], {j, 1, m + 1}]]; a[n_] := Coefficient[b[n, 0][[2]], x, 3]; Table[a[n], {n, 3, 25}] (* Jean-François Alcover, May 27 2018, translated from Maple *) CROSSREFS Column p=3 of A270236. Sequence in context: A139262 A026900 A016198 * A177257 A051140 A296631 Adjacent sequences: A270492 A270493 A270494 * A270496 A270497 A270498 KEYWORD nonn AUTHOR Alois P. Heinz, Mar 18 2016 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 March 20 07:37 EDT 2023. Contains 361363 sequences. (Running on oeis4.)