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A123486 Riordan array (1/(1-2x),x/(1-4x^2)). +0
1
1, 2, 1, 4, 2, 1, 8, 8, 2, 1, 16, 16, 12, 2, 1, 32, 48, 24, 16, 2, 1, 64, 96, 96, 32, 20, 2, 1, 128, 256, 192, 160, 40, 24, 2, 1, 256, 512, 640, 320, 240, 48, 28, 2, 1, 512 (list; table; graph; listen)
OFFSET

0,2

COMMENT

Row sums are A026581. Diagonal sums are A026383.

FORMULA

Number triangle T(n,k)=C(floor((n+k)/2),k)*2^(n-k)

EXAMPLE

Number triangle begins

1,

2, 1,

4, 2, 1,

8, 8, 2, 1,

16, 16, 12, 2, 1,

32, 48, 24, 16, 2, 1

CROSSREFS

Sequence in context: A123490 A157028 A060637 this_sequence A158264 A158982 A127124

Adjacent sequences: A123483 A123484 A123485 this_sequence A123487 A123488 A123489

KEYWORD

easy,nonn,tabl

AUTHOR

Paul Barry (pbarry(AT)wit.ie), Sep 30 2006

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Last modified November 23 17:09 EST 2009. Contains 167438 sequences.


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