A341922 Number of simple 3-connected triangulations of a disk with n nodes.

1, 1, 4, 15, 64, 293, 1414, 7102, 36809, 195676, 1062176, 5867676, 32901124, 186866589, 1073261418, 6225028476, 36420849235, 214744648169, 1275005642668, 7617704400227, 45772485843616, 276460659973100, 1677717692649544, 10225697003966360, 62575895785795084

Offset

4,3

Comments

A triangulation is simple if it contains no separating 3-cycle.

Links

Andrew Howroyd, Table of n, a(n) for n = 4..200

Example

The a(5) = 1 triangulation is:
      o-------o
      | \   / |
      |   o   |
      | /   \ |
      o-------o

Prog

(PARI) \\ R(n, m) defined in A210664.
seq(n)={my(v=R(n, 0)); for(m=1, n-1, v+=concat(vector(m), R(n-m, m))); v}

Crossrefs

Antidiagonal sums of A210664.

Sequence in context: A353264 A117669 A323789 * A007526 A233536 A349202

Adjacent sequences: A341919 A341920 A341921 * A341923 A341924 A341925

Keyword

nonn

Author

Andrew Howroyd, Feb 24 2021

Status

approved