A049340 Triangle read by rows: T(n,k) is the number of planar graphs with n >= 1 nodes and 0 <= k <= binomial(n,2) edges, all degrees even.

1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1, 1, 1, 3, 2, 2, 1, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 1, 3, 4, 4, 6, 5, 5, 3, 2, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 3, 4, 7, 9, 15, 17, 22, 14, 16, 5, 4, 0, 1, 0, 0, 0

Offset

1,32

Links

Sean A. Irvine, Table of n, a(n) for n = 1..231, rows 1..11 flattened

Sean A. Irvine, Java program (github)

Example

Triangle begins:
  1;
  1, 0;
  1, 0, 0, 1;
  1, 0, 0, 1, 1, 0, 0;
  1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0;
  1, 0, 0, 1, 1, 1, 3, 2, 2, 1, 1, 0, 1, 0, 0, 0;
  ...

Crossrefs

Rows sums give A049339.

Cf. A000944, A021103, A003094, A049334.

Sequence in context: A131961 A276426 A317872 * A336929 A325524 A010269

Adjacent sequences: A049337 A049338 A049339 * A049341 A049342 A049343

Keyword

nonn,tabf,easy,nice

Author

Brendan McKay

Extensions

Entry revised by Sean A. Irvine, Jul 29 2021

Status

approved