• 제목/요약/키워드: Riordan array

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A CHARACTERIZATION OF THE RIORDAN BELL SUBGROUP BY C-SEQUENCES

  • Jin, Sung-Tae
    • Korean Journal of Mathematics
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    • 제17권2호
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    • pp.147-154
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    • 2009
  • In this paper, we consider a new sequence called by the C-sequence of the Riordan array. It allows us to find a simple proof for several combinatorial identities. Further, we prove that a C-sequence characterizes Bell subgroup of the Riordan group.

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A LINK BETWEEN ORDERED TREES AND GREEN-RED TREES

  • CHEON, GI-SANG;KIM, HANA;SHAPIR, LOUIS W.
    • 대한수학회지
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    • 제53권1호
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    • pp.187-199
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    • 2016
  • The r-ary number sequences given by $$(b^{(r)}_n)_{n{\geq}0}=\Large{\frac{1}{(r-1)n+1}}(^{rn}_n)$$ are analogs of the sequence of the Catalan numbers ${\frac{1}{n+1}}(^{2n}_n)$. Their history goes back at least to Lambert [8] in 1758 and they are of considerable interest in sequential testing. Usually, the sequences are considered separately and the generalizations can go in several directions. Here we link the various r first by introducing a new combinatorial structure related to GR trees and then algebraically as well. This GR transition generalizes to give r-ary analogs of many sequences of combinatorial interest. It also lets us find infinite numbers of combinatorially defined sequences that lie between the Catalan numbers and the Ternary numbers, or more generally, between $b^{(r)}_n$ and $b^{(r+1)}_n$.