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A026998
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Triangular array T read by rows: T(n,k)=t(n,2k), t given by A027960, 0<=k<=n, n >= 0.
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19
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1, 1, 1, 1, 4, 1, 1, 4, 8, 1, 1, 4, 11, 13, 1, 1, 4, 11, 26, 19, 1, 1, 4, 11, 29, 54, 26, 1, 1, 4, 11, 29, 73, 101, 34, 1, 1, 4, 11, 29, 76, 171, 174, 43, 1, 1, 4, 11, 29, 76, 196, 370, 281, 53, 1, 1, 4, 11, 29, 76, 199, 487, 743, 431, 64, 1, 1, 4
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OFFSET
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0,5
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COMMENTS
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Right-edge columns are polynomials approximating Lucas(2n+1).
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LINKS
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Table of n, a(n) for n=0..67.
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FORMULA
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T(n, k) = Lucas(2n+1) = A002878(n) for 2k<=n, otherwise the (2n-2k)th coefficient of the power series for (1+2x)/{(1-x-x^2)(1-x)^(2k-n)}.
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EXAMPLE
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............................1
..........................1,1
........................1,4,1
......................1,4,8,1
..................1,4,11,13,1
...............1,4,11,26,19,1
............1,4,11,29,54,26,1
........1,4,11,29,73,101,34,1
....1,4,11,29,76,171,174,43,1
1,4,11,29,76,196,370,281,53,1
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CROSSREFS
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This is a bisection of the "Lucas array" A027960, see A027011 for the other bisection.
Row sums are in A000918. Right-edge columns include A034856, A027966, A027968, A027970, A027972.
Sequence in context: A091570 A116669 A016523 * A080061 A209571 A124258
Adjacent sequences: A026995 A026996 A026997 * A026999 A027000 A027001
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KEYWORD
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nonn,tabl
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AUTHOR
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Clark Kimberling
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EXTENSIONS
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Edited by Ralf Stephan, May 05 2005
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STATUS
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approved
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