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A143858 Number of pairwise disjoint unions of m integer-to-integer subintervals of [0,n]; a rectangular array by antidiagonals, n>=2m-1, m>=1. 5
1, 3, 1, 6, 5, 1, 10, 15, 7, 1, 15, 35, 28, 9, 1, 21, 70, 84, 45, 11, 1, 28, 126, 210, 165, 66, 13, 1, 36, 210, 462, 495, 286, 91, 15, 1, 45, 330, 924, 1287, 1001, 455, 120, 17, 1, 55, 495, 1716, 3003, 3003, 1820, 680, 153, 19, 1, 66, 715, 3003, 6435, 8008, 6188, 3060 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Main diagonal: A025174.

LINKS

Reinhard Zumkeller, Rows n = 1..125 of triangle, flattened

FORMULA

R(m,n) = C(n+1,2m), where n>=2m-1, m>=1. R is also given by the absolute values of terms in A109954.

EXAMPLE

R(2,4) counts these unions of 2 subintervals of [0,4]: [0,1]U[2,3], [0,1]U[2,4], [0,1]U[3,4], [0,2]U[3,4], [1,2]U[3,4].

PROG

(Haskell)  Seen as a triangle read by rows

a143858 n k = a143858_tabl !! (n-1) !! k

a143858_row n = a143858_tabl !! (n-1)

a143858_tabl = map ((++ [1]) . tail) a258993_tabl

-- Reinhard Zumkeller, Jun 22 2015

CROSSREFS

Cf. A007318, A025174, A109954, A085478, A258993.

Sequence in context: A208331 A061702 A112351 * A258993 A109954 A153641

Adjacent sequences:  A143855 A143856 A143857 * A143859 A143860 A143861

KEYWORD

nonn,tabf

AUTHOR

Clark Kimberling, Sep 03 2008

STATUS

approved

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Last modified August 16 10:22 EDT 2018. Contains 313797 sequences. (Running on oeis4.)