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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A188137 Riordan array (1, x*(1-x)/(1-3*x+x^2)). 3
 1, 2, 1, 5, 4, 1, 13, 14, 6, 1, 34, 46, 27, 8, 1, 89, 145, 107, 44, 10, 1, 233, 444, 393, 204, 65, 12, 1, 610, 1331, 1371, 854, 345, 90, 14, 1, 1597, 3926, 4607, 3336, 1620, 538, 119, 16, 1, 4181, 11434, 15045, 12390, 6997, 2799, 791, 152, 18, 1 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS The column of index 0 contains a 1 followed by zeros and is not reproduced in this triangle. The second argument of the array definition is A(x) = A000045(x/(1-x)) = A001519(x)-1. Triangle T(n,k), 1 <= k <= n, given by (0, 2, 1/2, 1/2, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (1, 0, 0, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938. - Philippe Deléham, Jan 26 2012 LINKS Alois P. Heinz, Rows n = 1..141, flattened Milan Janjić, Words and Linear Recurrences, J. Int. Seq. 21 (2018), #18.1.4. Vladimir Kruchinin and D. V. Kruchinin, Composita and their properties, arXiv:1103.2582 [math.CO], 2011-2013. FORMULA T(n,m) = Sum_{k=m..n} binomial(n-1,k-1) * Sum_{i=ceiling((k-m)/2)..k-m} binomial(i,k-m-i)*binomial(m+i-1,m-1), 0

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 April 1 08:54 EDT 2023. Contains 361681 sequences. (Running on oeis4.)