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A121576 Riordan array (2-2x-sqrt(1-8x+4x^2),(1-2x-sqrt(1-8x+4x^2))/2). +0
3
1, 2, 1, 6, 5, 1, 24, 24, 8, 1, 114, 123, 51, 11, 1, 600, 672, 312, 87, 14, 1, 3372, 3858, 1914, 618, 132, 17, 1, 19824, 22992, 11904, 4218, 1068, 186, 20, 1, 120426, 140991, 75183, 28383, 8043, 1689, 249, 23, 1, 749976, 884112, 481704, 190347, 58398, 13929 (list; table; graph; listen)
OFFSET

0,2

COMMENT

Inverse of Riordan array (1/(1+2x),x(1-x)/(1+2x)). Row sums are A047891; first column is A054872. Signed version given by A121575.

Triangle T(n,k), 0<=k<=n, read by rows, given by [2, 1, 3, 1, 3, 1, 3, 1, 3, ...] DELTA [1, 0, 0, 0, 0, 0, 0, 0, 0, ...] where DELTA is the operator defined in A084938 . - Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Aug 09 2006

EXAMPLE

Triangle begins

1,

2,1,

6,5,1,

24,24,8,1,

114,123,51,11,1,

600,672,312,87,14,1,

3372,3858,1914,618,132,17,1

CROSSREFS

Sequence in context: A055896 A116395 A133367 this_sequence A121575 A049444 A136124

Adjacent sequences: A121573 A121574 A121575 this_sequence A121577 A121578 A121579

KEYWORD

easy,nonn,tabl

AUTHOR

Paul Barry (pbarry(AT)wit.ie), Aug 08 2006

page 1

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Last modified August 19 23:53 EDT 2008. Contains 142930 sequences.


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