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 A274781 Diagonal of the rational function 1/(1 - x - y - z - x y - x y z). 1
 1, 9, 187, 4893, 141771, 4352799, 138747631, 4540248813, 151482515587, 5130182907699, 175813106080437, 6083513738182923, 212190873229751079, 7451115041129234211, 263154860370419749527, 9340227180994323327213, 332954350987408603124067, 11914280614112222340359211 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Annihilating differential operator: x*(5*x^2-12*x-6)*(x^4-13*x^3+77*x^2-78*x+2)* Dx^2 + (15*x^6-178*x^5+823*x^4-1536*x^3-460*x^2+936*x-12)*Dx + 5*x^5-39*x^4+48*x^3+48*x^2-420*x+108. LINKS Gheorghe Coserea, Table of n, a(n) for n = 0..310 A. Bostan, S. Boukraa, J.-M. Maillard, J.-A. Weil, Diagonals of rational functions and selected differential Galois groups, arXiv preprint arXiv:1507.03227 [math-ph], 2015. FORMULA G.f.: hypergeom([1/12,5/12],[1],1728*x^3*(x^4-13*x^3+77*x^2-78*x+2)/(x^4-12*x^3+62*x^2-36*x+1)^3)/(x^4-12*x^3+62*x^2-36*x+1)^(1/4). 0 = x*(5*x^2-12*x-6)*(x^4-13*x^3+77*x^2-78*x+2)*y'' + (15*x^6-178*x^5+823*x^4-1536*x^3-460*x^2+936*x-12)*y' + (5*x^5-39*x^4+48*x^3+48*x^2-420*x+108)*y, where y is g.f. Recurrence: 2*n^2*(571*n^2 - 2169*n + 1898)*a(n) = 6*(7423*n^4 - 35620*n^3 + 54454*n^2 - 30721*n + 5364)*a(n-1) - (43967*n^4 - 254947*n^3 + 507958*n^2 - 395102*n + 87336)*a(n-2) + (7423*n^4 - 50466*n^3 + 117650*n^2 - 104391*n + 24732)*a(n-3) - (n-3)^2*(571*n^2 - 1027*n + 300)*a(n-4). - Vaclav Kotesovec, Jul 07 2016 MATHEMATICA a[n_] := SeriesCoefficient[1/(1 - x - y - z - x y - x y z), {x, 0, n}, {y, 0, n}, {z, 0, n}]; Table[a[n], {n, 0, 17}] (* Jean-François Alcover, Oct 23 2018 *) PROG (PARI) my(x='x, y='y, z='z); R = 1/(1 - x - y - z - x*y - x*y*z); diag(n, expr, var) = {   my(a = vector(n));   for (i = 1, #var, expr = taylor(expr, var[#var - i + 1], n));   for (k = 1, n, a[k] = expr;        for (i = 1, #var, a[k] = polcoeff(a[k], k-1)));   return(a); }; diag(10, R, [x, y, z]) (PARI) system("wget http://www.jjj.de/pari/hypergeom.gpi"); read("hypergeom.gpi"); N = 20; x = 'x + O('x^N); Vec(hypergeom([1/12, 5/12], [1], 1728*x^3*(x^4-13*x^3+77*x^2-78*x+2)/(x^4-12*x^3+62*x^2-36*x+1)^3, N)/(x^4-12*x^3+62*x^2-36*x+1)^(1/4)) CROSSREFS Cf. A268545-A268555. Sequence in context: A216409 A171194 A196297 * A293848 A266496 A078101 Adjacent sequences:  A274778 A274779 A274780 * A274782 A274783 A274784 KEYWORD nonn AUTHOR Gheorghe Coserea, Jul 06 2016 STATUS approved

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Last modified September 24 14:00 EDT 2020. Contains 337321 sequences. (Running on oeis4.)