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A108959 Triangle arising in connection with deformations of type D Kleinian singularities. 0
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 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

P. Boddington, Ph.D. thesis, University of Warwick, 2005.

LINKS

Table of n, a(n) for n=0..37.

FORMULA

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. Eg x^3 goes to 3x^2+4x+2.

CROSSREFS

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

KEYWORD

easy,nonn,tabl

AUTHOR

Paul Boddington, Jul 22 2005

STATUS

approved

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Last modified April 24 04:21 EDT 2019. Contains 322406 sequences. (Running on oeis4.)