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A225621
Central terms of the triangle in A074911.
3
1, 4, 20, 108, 632, 4060, 28968, 231000, 2058096, 20375964, 222393800, 2653879624, 34365597840, 479776469848, 7181892528272, 114731622081840, 1948073992109280, 35031456100431900, 665075537735997960, 13292908401187179240, 279000321119414475600
OFFSET
1,2
COMMENTS
a(n) = A074911(2*n-1,n).
PROG
(Haskell)
a225621 n = a074911 (2 * n - 1) n
CROSSREFS
Cf. A227791.
Sequence in context: A319321 A321574 A377583 * A375303 A020084 A325956
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Aug 05 2013
STATUS
approved