A047771 Number of dissectable polyhedra with n tetrahedral cells and symmetry of type L.

0, 0, 0, 0, 0, 1, 0, 8, 0, 42, 0, 232, 0, 1277, 0, 7183, 0, 41041, 0, 238315, 0, 1402076, 0, 8343804, 0, 50136483, 0, 303790544, 0, 1854115285, 0, 11388104153, 0, 70338364135, 0, 436605050440, 0, 2722153369473, 0, 17040017600925, 0

Offset

1,8

Comments

One of 17 different symmetry types comprising A007173 and A027610 and one of 10 for A371351. Also the number of tetrahedral clusters or polyominoes of the regular tiling with Schläfli symbol {3,3,oo}, both having type L achiral symmetry and n tetrahedral cells. The plane of symmetry is a tetrahedral face (210); the order of the symmetry group is 2. An achiral polyomino is identical to its reflection. - Robert A. Russell, Mar 22 2024

Links

Table of n, a(n) for n=1..41.

L. W. Beineke and R. E. Pippert, Enumerating dissectable polyhedra by their automorphism groups, Canad. J. Math., 26 (1974), 50-67.

Robert A. Russell, Mathematica Graphics3D program for A047771 example.

Formula

If n=2m then (1/6)*(A001764(m) - 2*A047766(n) - 3*A047765(n) - A047764(n)), otherwise 0.

G.f.: (2 + G(z^2) - z^2*G(z^6)) / 6 - (G(z^4) + z^2*G(z^4)^2 - z^2*G(z^12) - z^8*G(z^12)^2) / 2, where G(z) = 1 + z*G(z)^3 is the g.f. for A001764. - Robert A. Russell, Mar 30 2024

Mathematica

Table[(If[OddQ[n], 0, Binomial[3n/2, n/2]/(n+1)-6If[OddQ[n/2], 2Binomial[(3n-2)/4, (n-2)/4], Binomial[3n/4, n/4]]/(n+2)]-3If[2==Mod[n, 6], Binomial[3(n-2)/6, (n-2)/6]/(n+1)-If[2==Mod[n, 12], 6Binomial[3(n-2)/12, (n-2)/12], 12Binomial[n/4-1, (n-8)/12]]/(n+4), 0])/6, {n, 30}] (* Robert A. Russell, Mar 22 2024 *)

Crossrefs

Cf. A047772.

Cf. A007173 (oriented), A027610 (unoriented), A371351 (achiral), A001764 (rooted), A047764 (type Q), A047765 (type P), A047766 (type N).

Sequence in context: A187162 A197618 A340953 * A298099 A137528 A270006

Adjacent sequences: A047768 A047769 A047770 * A047772 A047773 A047774

Keyword

nonn

Author

N. J. A. Sloane

Status

approved