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A230585
First terms of first rows of zigzag matrices as defined in A088961.
2
3, 5, 14, 42, 132, 429, 1430, 4862, 16796, 58786, 208012, 742900, 2674440, 9694845, 35357670, 129644790, 477638700, 1767263190, 6564120420, 24466267020, 91482563640, 343059613650, 1289904147324, 4861946401452, 18367353072152, 69533550916004, 263747951750360
OFFSET
1,1
COMMENTS
a(n) = A088961(A056520(n-1));
a(n) = A000108(n+1) for n > 1.
LINKS
FORMULA
a(n) = binomial(2*n,n) - binomial(2*n,n+2) + 0^(n-1).
PROG
(Haskell)
a230585 1 = 3
a230585 n = a007318 (2*n) n - a007318 (2*n) (n+2)
CROSSREFS
Cf. A007318.
Sequence in context: A284415 A318227 A363542 * A006395 A078718 A081393
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Oct 25 2013
STATUS
approved