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A181657
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Generalized (conditional) Riordan array with k-th column generated by x^k * (1 + x - x^2 + x^3)/(1 - 2x^2 - x^4) if k mod 2 = 0, x^k * (1+x)/(1 - 2x^2 - x^4) otherwise.
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2
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1, 1, 1, 1, 1, 1, 3, 2, 1, 1, 3, 2, 1, 1, 1, 7, 5, 3, 2, 1, 1, 7, 5, 3, 2, 1, 1, 1, 17, 12, 7, 5, 3, 2, 1, 1, 17, 12, 7, 5, 3, 2, 1, 1, 1, 41, 29, 17, 12, 7, 5, 3, 2, 1, 1, 41, 29, 17, 12, 7, 5, 3, 2, 1, 1, 1
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OFFSET
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0,7
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COMMENTS
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An eigentriangle of A181656. Even columns are essentially A001333 doubled. Odd columns are doubled Pell numbers (A000129).
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LINKS
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EXAMPLE
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Triangle begins
1;
1, 1;
1, 1, 1;
3, 2, 1, 1;
3, 2, 1, 1, 1;
7, 5, 3, 2, 1, 1;
7, 5, 3, 2, 1, 1, 1;
17, 12, 7, 5, 3, 2, 1, 1;
17, 12, 7, 5, 3, 2, 1, 1, 1;
41, 29, 17, 12, 7, 5, 3, 2, 1, 1;
41, 29, 17, 12, 7, 5, 3, 2, 1, 1, 1;
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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