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A335749
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a(n) = n!*[x^n] exp(2*x)*(y*sinh(x*y) + cosh(x*y)) and y = sqrt(6).
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2
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1, 8, 34, 152, 676, 3008, 13384, 59552, 264976, 1179008, 5245984, 23341952, 103859776, 462123008, 2056211584, 9149092352, 40708792576, 181133355008, 805951005184, 3586070730752, 15956184933376, 70996881195008, 315899894646784, 1405593340977152, 6254173153202176
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OFFSET
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0,2
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LINKS
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FORMULA
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G.f.: (1 + 4*x) / (1 - 4*x - 2*x^2) for n>1.
a(n) = 4*a(n-1) + 2*a(n-2). (End)
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MAPLE
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aList := proc(len) local H; H := (x, y) -> exp(2*x)*(y*sinh(x*y) + cosh(x*y)):
series(H(x, sqrt(6)), x, len + 1): seq(k!*coeff(%, x, k), k=0..len-1) end:
aList(25);
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MATHEMATICA
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LinearRecurrence[{4, 2}, {1, 8}, 30] (* Paolo Xausa, Feb 01 2024 *)
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PROG
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(PARI) Vec((1 + 4*x) / (1 - 4*x - 2*x^2) + O(x^25)) \\ Colin Barker, Jun 25 2020
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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