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 A021010 Triangle of coefficients of Laguerre polynomials L_n(x) (powers of x in decreasing order). 7
 1, -1, 1, 1, -4, 2, -1, 9, -18, 6, 1, -16, 72, -96, 24, -1, 25, -200, 600, -600, 120, 1, -36, 450, -2400, 5400, -4320, 720, -1, 49, -882, 7350, -29400, 52920, -35280, 5040, 1, -64, 1568, -18816, 117600, -376320, 564480, -322560, 40320, -1, 81, -2592, 42336, -381024, 1905120, -5080320, 6531840, -3265920, 362880 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 COMMENTS abs(T(n,k)) = k!*binomial(n,k)^2 = number of k-matchings of the complete bipartite graph K_{n,n}. Example: abs(T(2,2))=2 because in the bipartite graph K_{2,2} with vertex sets {A,B},{A',B'} we have the 2-matchings {AA',BB'} and {AB',BA'}. Row sums of the absolute values yield A002720. - Emeric Deutsch, Dec 25 2004 REFERENCES M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 799. LINKS T. D. Noe, Rows n=0..50 of triangle, flattened M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy]. J. Fernando Barbero G., Jesús Salas, Eduardo J. S. Villaseñor, Bivariate Generating Functions for a Class of Linear Recurrences. I. General Structure, arXiv:1307.2010 [math.CO], 2013. C. Lanczos, Applied Analysis (Annotated scans of selected pages) See page 519. Eric Weisstein's World of Mathematics, Rook Polynomial FORMULA T(n, k) = (-1)^(n-k)*k!*binomial(n, k)^2. - Emeric Deutsch, Dec 25 2004 EXAMPLE 1;   -1,   1;    1,  -4,   2;   -1,   9, -18,   6;    1, -16,  72, -96,  24;   ... MAPLE T:=(n, k)->(-1)^(n-k)*k!*binomial(n, k)^2: for n from 0 to 9 do seq(T(n, k), k=0..n) od; # yields sequence in triangular form # Emeric Deutsch, Dec 25 2004 MATHEMATICA Flatten[ Table[ Reverse[ CoefficientList[n!*LaguerreL[n, x], x]], {n, 0, 9}]] (* Jean-François Alcover, Nov 24 2011 *) PROG (PARI) LaguerreL(n, v='x) = {   my(x='x+O('x^(n+1)), t='t);   subst(polcoeff(exp(-x*t/(1-x))/(1-x), n), 't, v); }; concat(apply(n->Vec(n!*LaguerreL(n)), [0..9])) \\ Gheorghe Coserea, Oct 26 2017 (PARI) row(n) = Vec(n!*pollaguerre(n)); \\ Michel Marcus, Feb 06 2021 (MAGMA) [[(-1)^(n-k)*Factorial(k)*Binomial(n, k)^2: k in [0..n]]: n in [0..10]]; // G. C. Greubel, Feb 06 2018 CROSSREFS Cf. A002720, A021009. Central terms: A295383. Sequence in context: A063983 A259985 A144084 * A342088 A193607 A075397 Adjacent sequences:  A021007 A021008 A021009 * A021011 A021012 A021013 KEYWORD sign,tabl,easy,nice AUTHOR STATUS approved

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Last modified April 21 14:32 EDT 2021. Contains 343154 sequences. (Running on oeis4.)