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A123486
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Riordan array (1/(1-2x),x/(1-4x^2)).
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0
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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; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| Row sums are A026581. Diagonal sums are A026383.
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FORMULA
| Number triangle T(n,k)=C(floor((n+k)/2),k)*2^(n-k)
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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
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CROSSREFS
| Sequence in context: A123490 A157028 A060637 * A158264 A158982 A127124
Adjacent sequences: A123483 A123484 A123485 * A123487 A123488 A123489
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KEYWORD
| easy,nonn,tabl
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AUTHOR
| Paul Barry (pbarry(AT)wit.ie), Sep 30 2006
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