The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A086211 Triangle related to Bell numbers; T(n,k) read by rows, n>=0, 0<=k<=n: T(n,k) = k*T(n-1,k) + Sum(0<=j, T(n-1,k-1+j)); T(0,0)=1, T(0,k)=0 if k>0. 3
 1, 1, 1, 2, 3, 1, 6, 9, 6, 1, 22, 31, 28, 10, 1, 92, 123, 126, 69, 15, 1, 426, 549, 586, 418, 145, 21, 1, 2146, 2695, 2892, 2425, 1165, 272, 28, 1, 11624, 14319, 15262, 14058, 8551, 2826, 469, 36, 1 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 COMMENTS With offset 1 for k, T(n,k) is the number of indecomposable set partitions of [n+2] in which 1 is in the k-th block when the blocks are arranged in order of increasing largest entry. For example, T(2,2)=3 counts 2/134, 23/14, 3/124; see Link. - David Callan, Aug 30 2014 LINKS David Callan, A combinatorial interpretation for this sequence Chunyan Yan, Zhicong Lin, Inversion sequences avoiding pairs of patterns, arXiv:1912.03674 [math.CO], 2019. FORMULA Sum(k=0..n, A000110(k)*T(n-k,0)) = A000110(n+1). Sum_{k=0..n} T(n, k) = A074664(n+2). - Philippe Deléham, May 10 2005 EXAMPLE Triangle begins: 1; 1, 1; 2, 3, 1; 6, 9, 6, 1; 22, 31, 28, 10, 1; 92, 123, 126, 69, 15, 1; 426, 549, 586, 418, 145, 21, 1; 2146, 2695, 2892, 2425, 1165, 272, 28, 1; 11624, 14319, 15262, 14058, 8551, 2826, 469, 36, 1 ; ... CROSSREFS Cf. A000110. Sequence in context: A347766 A198427 A289905 * A110189 A187914 A321625 Adjacent sequences:  A086208 A086209 A086210 * A086212 A086213 A086214 KEYWORD nonn,tabl AUTHOR Philippe Deléham, Aug 27 2003, Jun 16 2007 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 September 24 14:33 EDT 2021. Contains 347643 sequences. (Running on oeis4.)