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0, 8, 52, 372, 2894, 23966, 208086, 1874508, 17390158, 165248499, 1601857338, 15790898316, 157915304928, 1598927475749, 16365689821454, 169113248927772, 1762344520554606, 18504654979649615, 195620858324078190, 2080695883684277190, 22254407183551916850
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internal format)
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OFFSET
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0,2
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COMMENTS
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Number of separable rooted planar maps with n+1 edges. - Noam Zeilberger, Dec 26 2022
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LINKS
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FORMULA
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a(n) ~ ((48^(n + 1) - 3^(3*n + 1/2)))/(2^(2*n + 1)*sqrt(Pi)*n^(5/2)). - Peter Luschny, Dec 26 2022
D-finite with recurrence -2*(389*n-1012)*(2*n+1)*(n+3)*(n+1)*a(n) +3*(14101*n^4-20062*n^3-56389*n^2+45022*n-6072)*a(n-1) +18*(-20677*n^4+100317*n^3-137223*n^2+14267*n+52524)*a(n-2) +108*(547*n-956)*(3*n-7)*(2*n-3)*(3*n-8)*a(n-3)=0. - R. J. Mathar, Jan 25 2023
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MAPLE
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a := n -> 2*(3^(n + 1)*(2*n + 2)!/(n + 3)! - (3*n)!/(2*n + 1)!)/(n + 1)!:
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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