cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A047758 Number of chiral pairs of dissectable polyhedra with n tetrahedral cells and symmetry of type G.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 8, 0, 0, 0, 42, 0, 0, 0, 232, 0, 0, 0, 1277, 0, 0, 0, 7183, 0, 0, 0, 41041, 0, 0, 0, 238315, 0, 0, 0, 1402076, 0, 0, 0, 8343804, 0, 0, 0, 50136483, 0, 0, 0, 303790544, 0, 0, 0, 1854115285, 0, 0, 0, 11388104153
Offset: 1

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Comments

One of 17 different symmetry types comprising A007173 and A027610 and one of 7 for A371350. Also the number of tetrahedral clusters or polyominoes of the regular tiling with Schläfli symbol {3,3,oo}, both having type G chiral symmetry and n tetrahedral cells. The axis of symmetry is a line connecting the centers of opposite edges of a tetrahedral cell (31); the order of the symmetry group is 4. Each member of a chiral pair is a reflection but not a rotation of the other. - Robert A. Russell, Mar 22 2024

Crossrefs

Cf. A047772.
Cf. A007173 (oriented), A027610 (unoriented), A371350 (chiral), A001764 (rooted), A047751 (type K), A047752 (type J), A047753 (type I).

Programs

  • Mathematica
    Table[If[1==Mod[n,4],(2Boole[1==n]+2Binomial[(3n-3)/4,(n-1)/4]/(n+1)-If[1==Mod[n,8],12Binomial[(3n-3)/8,(n-1)/8]/(n+3),12Binomial[(3n-7)/8,(n+3)/8]/(n-1)]-If[5==Mod[n,12],6Binomial[(n-5)/4,(n-5)/12]/(n+1)-If[5==Mod[n,24],36Binomial[(n-5)/8,(n-5)/12],72Binomial[(n-9)/8,(n-17)/24]]/(n+7),0])/6,0],{n,50}] (* Robert A. Russell, Mar 22 2024 *)

Formula

If n=4m+1 then (1/6)*(A001764(m) - 3*A047753(n) - 2*A047752(n) - A047751(n)), otherwise 0.
G.f.: z * (2 + G(z^4) - z^4*G(z^12) - 3 * (G(z^8) + z^4*G(z^8)^2 - z^4*G(z^24) - z^16*G(z^24)^2)) / 6, where G(z) = 1 + z*G(z)^3 is the g.f. for A001764. - Robert A. Russell, Mar 22 2024