A286951 Irregular triangle read by rows: T(n,k) is the number of graphs with n vertices with matching number k (0 <= k <= floor(n/2)).

1, 1, 1, 1, 1, 3, 1, 4, 6, 1, 5, 28, 1, 6, 48, 101, 1, 7, 73, 963, 1, 8, 106, 1818, 10413, 1, 9, 147, 3383, 271128, 1, 10, 198, 6129, 441031, 11557799

Offset

0,6

Links

Table of n, a(n) for n=0..35.

Eric Weisstein's World of Mathematics, Matching Number

Example

Triangle begins:
  1;
  1;
  1, 1;
  1, 3;
  1, 4,  6;
  1, 5,  28;
  1, 6,  48,  101;
  1, 7,  73,  963;
  1, 8, 106, 1818, 10413;
  ...

Crossrefs

Row sums are A000088.

T(2n,n) gives A218462 (for n>0).

Sequence in context: A108285 A207619 A209694 * A260355 A075419 A060922

Adjacent sequences: A286948 A286949 A286950 * A286952 A286953 A286954

Keyword

nonn,tabf

Author

Eric W. Weisstein, May 17 2017

Extensions

Name corrected by Andrew Howroyd, Nov 04 2017

T(0,0)=1 added by Alois P. Heinz, Nov 04 2017

Status

approved