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Number of nonequivalent dissections of a polygon into n pentagons by nonintersecting diagonals rooted at a cell up to rotation and reflection.
(Formerly M3589)
3

%I M3589 #28 Jan 17 2018 11:40:01

%S 1,1,4,22,147,1074,8216,64798,521900,4272967,35447724,297308810,

%T 2516830890,21476307960,184530904560,1595190209002,13863857007924,

%U 121067796450692,1061770618201680,9347742325179544,82584606893075739

%N Number of nonequivalent dissections of a polygon into n pentagons by nonintersecting diagonals rooted at a cell up to rotation and reflection.

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H Vaclav Kotesovec, <a href="/A005039/b005039.txt">Table of n, a(n) for n = 1..1000</a>

%H F. Harary, E. M. Palmer, R. C. Read, <a href="/A000108/a000108_20.pdf">On the cell-growth problem for arbitrary polygons, computer printout, circa 1974</a>

%H F. Harary, E. M. Palmer and R. C. Read, <a href="http://dx.doi.org/10.1016/0012-365X(75)90041-2">On the cell-growth problem for arbitrary polygons</a>, Discr. Math. 11 (1975), 371-389.

%F G.f.: (1/10)*x*(u^5(x) + 4*u(x^5) + 5*u^2(x^2) + 5*x*u^4(x^2)) where u(x) is the g.f. for A002293. - _Sean A. Irvine_, Mar 12 2016

%F a(n) ~ 2^(8*n - 1/2) / (sqrt(Pi) * n^(3/2) * 3^(3*n + 5/2)). - _Vaclav Kotesovec_, Mar 13 2016

%t Rest[CoefficientList[Series[x*(HypergeometricPFQ[{1/4, 1/2, 3/4}, {2/3, 4/3}, (256/27)*x]^5 + 4*HypergeometricPFQ[{1/4, 1/2, 3/4}, {2/3, 4/3}, (256/27)*x^5] + 5*HypergeometricPFQ[{1/4, 1/2, 3/4}, {2/3, 4/3}, (256/27)*x^2]^2 + 5*x*HypergeometricPFQ[{1/4, 1/2, 3/4}, {2/3, 4/3}, (256/27)*x^2]^4)/10, {x, 0, 25}], x]] (* _Vaclav Kotesovec_, Mar 13 2016 *)

%Y Column k=5 of A295259.

%Y Cf. A002293, A005037 (no mirror-image symmetries), A003446 (triangles), A005035 (quadrilaterals).

%K nonn

%O 1,3

%A _N. J. A. Sloane_

%E More terms from _Sean A. Irvine_, Mar 12 2016

%E Name edited by _Andrew Howroyd_, Nov 20 2017