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A088015
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Expansion of e.g.f. cosh(sqrt(2)*x) + exp(x)*(cosh(sqrt(2)*x) - 1).
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1
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1, 0, 4, 6, 20, 40, 106, 238, 592, 1392, 3394, 8118, 19664, 47320, 114370, 275806, 666112, 1607520, 3881410, 9369318, 22620560, 54608392, 131838370, 318281038, 768402496, 1855077840, 4478562274, 10812186006, 26102942480, 63018038200
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OFFSET
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0,3
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COMMENTS
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This sequence is A000079 (with interpolated zeros) + 2*(A048739 (with two leading zeros)).
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LINKS
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FORMULA
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G.f.: (1 -3*x +3*x^2 +x^3 -4*x^4)/((1-x)*(1-2*x-3*x^2+4*x^3+2*x^4)).
E.g.f. : cosh(sqrt(2)x)+exp(x)(cosh(sqrt(2)x)-1);
a(n) = ((sqrt(2))^n +(-sqrt(2))^n +(1+sqrt(2))^n +(1-sqrt(2))^n)/2 -1.
G.f.: ( -1-3*x^2-x^3+4*x^4+3*x ) / ( (x-1)*(2*x^2-1)*(x^2+2*x-1) ). - R. J. Mathar, Dec 10 2014
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MATHEMATICA
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LinearRecurrence[{3, 1, -7, 2, 2}, {1, 0, 4, 6, 20}, 30] (* Harvey P. Dale, May 05 2018 *)
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PROG
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(PARI) x='x+O('x^30); Vec((1 -3*x +3*x^2 +x^3 -4*x^4)/((1-x)*(1-2*x-3*x^2+4*x^3+2*x^4))) \\ G. C. Greubel, Sep 27 2018
(Magma) m:=30; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!((1 -3*x +3*x^2 +x^3 -4*x^4)/((1-x)*(1-2*x-3*x^2+4*x^3+2*x^4)))); // G. C. Greubel, Sep 27 2018
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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