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A181657 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. 2
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 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
0,7
COMMENTS
An eigentriangle of A181656. Even columns are essentially A001333 doubled. Odd columns are doubled Pell numbers (A000129).
Row sums are A181658.
LINKS
EXAMPLE
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;
CROSSREFS
Sequence in context: A083716 A231820 A010268 * A172254 A053542 A087284
KEYWORD
easy,nonn,tabl
AUTHOR
Paul Barry, Nov 03 2010
STATUS
approved

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Last modified February 27 16:21 EST 2024. Contains 370378 sequences. (Running on oeis4.)