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%I #16 Jan 19 2020 13:33:04
%S 1,24,200,1052,3994,12292,32088,74320,155986,303512,553520,958636,
%T 1586554,2529708,3900872,5848984,8548370,12224144,17131328,23593828,
%U 31968890,42705180,56285952,73313624,94423970,120405112,152074032,190440188,236532474,291620356
%N Susceptibility series H_6 for 2-dimensional Ising model (divided by 2).
%H Colin Barker, <a href="/A055857/b055857.txt">Table of n, a(n) for n = 0..1000</a>
%H A. J. Guttmann and I. G. Enting, <a href="https://doi.org/10.1103/PhysRevLett.76.344">Solvability of some statistical mechanical systems</a>, Phys. Rev. Lett., 76 (1996), 344-347.
%H <a href="/index/Rec#order_18">Index entries for linear recurrences with constant coefficients</a>, signature (-1,4,7,-3,-18,-11,19,29,0,-29,-19,11,18,3,-7,-4,1,1).
%F G.f.: (1+x^18+25*(x+x^17)+220*(x^2+x^16)+1149*(x^3+x^15)+ 4081*(x^4+x^14)+10768*(x^5+x^13)+22083*(x^6+x^12)+36283*(x^7+x^11)+ 48543*(x^8+x^10)+53446*x^9) / (((1-x^3)^3)*(1-x)^4*(1+x)^5).
%t CoefficientList[Series[(1+25*x+220*x^2+1149*x^3+4081*x^4+10768*x^5+22083*x^6 +36283*x^7+48543*x^8+53446*x^9+48543*x^10+36283*x^11+22083*x^12+10768*x^13 + 4081*x^14+1149*x^15+220*x^16+25*x^17+x^18)/((1+x)*(1-x^2)^4*(1-x^3)^3), {x,0, 30}], x] (* _G. C. Greubel_, Jan 17 2020 *)
%o (PARI) Vec((1 +25*x +220*x^2 +1149*x^3 +4081*x^4 +10768*x^5 +22083*x^6 +36283*x^7 +48543*x^8 +53446*x^9 +48543*x^10 +36283*x^11 +22083*x^12 +10768*x^13 +4081*x^14 +1149*x^15 +220*x^16 +25*x^17 +x^18) / ((1 -x)^7*(1 +x)^5*(1 +x +x^2)^3) + O(x^50)) \\ _Colin Barker_, Dec 10 2016
%Y Cf. A054275, A054389, A054410, A054764, A055856.
%K nonn,easy
%O 0,2
%A _Wolfdieter Lang_, Jun 07 2000
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