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A002624 Expansion of (1-x)^-3 (1-x^2 )^-2.
(Formerly M2723 N1091)
9
1, 3, 8, 16, 30, 50, 80, 120, 175, 245, 336, 448, 588, 756, 960, 1200, 1485, 1815, 2200, 2640, 3146, 3718, 4368, 5096, 5915, 6825, 7840, 8960, 10200, 11560, 13056, 14688, 16473, 18411, 20520, 22800, 25270, 27930, 30800, 33880, 37191, 40733, 44528 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

COMMENTS

Contribution from Gary W. Adamson (qntmpkt(AT)yahoo.com), Mar 02 2010: (Start)

Given an irregular triangular matrix M with the triangular series in every

column shifted down twice for columns >0, A002624 = M * [1, 2, 3,...].

Example: row 4 of triangle M = (15, 6, 1), then (15, 6, 1) dot (1, 2, 3) =

a(4) = 30 = (15 + 12 + 3). (End)

The Kn21, Kn22, Kn23, Fi2 and Ze2 triangle sums of A139600 are related to the sequence given above, e.g. Ze2(n) = A002624(n-1) - A002624(n-2) - A002624(n-3) + 4*A002624(n-4), with A002624(n) = 0 for n <= -1. For the definitions of these triangle sums see A180662. [From Johannes W. Meijer, Apr 29 2011]

REFERENCES

E. Fix and J. L. Hodges, Jr., Significance probabilities of the Wilcoxon test, Annals Math. Stat., 26 (1955), 301-312.

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..10000

INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 204

S. Plouffe, Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.

S. Plouffe, 1031 Generating Functions and Conjectures, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.

Index to sequences with linear recurrences with constant coefficients, signature (3,-1,-5,5,1,-3,1).

FORMULA

a(n-1)= ( n^4 +10*n^3 +32*n^2 +32*n +(6*n +15)*(n mod 2) )/96.

MAPLE

A002624:=-1/(z+1)**2/(z-1)**5; [S. Plouffe in his 1992 dissertation.]

MATHEMATICA

f[n_] := Block[{m = n - 1}, (m^4 + 10m^3 + 32m^2 + 32m + (6m + 15)Mod[m, 2])/96]; Table[ f[n], {n, 2, 45}]

(* Or *) CoefficientList[ Series[1/((1 - x)^3 (1 - x^2)^2), {x, 0, 44}], x] (from Robert G. Wilson v, Feb 26 2005)

PROG

(MAGMA) [( (n+1)^4 +10*(n+1)^3 +32*(n+1)^2 +32*(n+1) +(6*(n+1) +15)*((n+1) mod 2) )/96 : n in [0..50]]; // Vincenzo Librandi, Oct 08 2011

CROSSREFS

Sequence in context: A167616 A009439 A000233 * A068039 A188123 A081661

Adjacent sequences:  A002621 A002622 A002623 * A002625 A002626 A002627

KEYWORD

nonn

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

EXTENSIONS

Formula and more terms from Frank.Ellermann(AT)t-online.de, Mar 14 2002

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Last modified February 15 15:14 EST 2012. Contains 205823 sequences.