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A108959
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Triangle arising in connection with deformations of type D Kleinian singularities.
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0
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1, 2, 1, 3, 4, 2, 4, 10, 14, 7, 5, 20, 54, 76, 38, 6, 35, 154, 419, 590, 295, 7, 56, 364, 1616, 4400, 6196, 3098, 8, 84, 756, 4962, 22048, 60036, 84542, 42271, 9, 120
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OFFSET
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0,2
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REFERENCES
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P. Boddington, Ph.D. thesis, University of Warwick, 2005.
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LINKS
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Table of n, a(n) for n=0..37.
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FORMULA
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For k>=0 define p_k(x) = x(x+1)(x+3)...(x+k(k-1)/2) and consider the linear map taking each p_k(x) to kp_k(x)/x. Then the images of x, x^2, x^3, ... are given by the rows. E.g., x^3 goes to 3x^2 + 4x + 2.
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CROSSREFS
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This sequence is an improved version of A097418. Coefficients of 1 give A000366.
Sequence in context: A245334 A102756 A086614 * A208750 A107893 A131987
Adjacent sequences: A108956 A108957 A108958 * A108960 A108961 A108962
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KEYWORD
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easy,nonn,tabl
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AUTHOR
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Paul Boddington, Jul 22 2005
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STATUS
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approved
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