A334546 - OEIS

A334546

Array read by antidiagonals: T(n,k) is the number of unlabeled connected loopless multigraphs with n nodes of degree k or less.

1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 2, 0, 0, 1, 1, 3, 2, 0, 0, 1, 1, 4, 4, 2, 0, 0, 1, 1, 5, 9, 12, 2, 0, 0, 1, 1, 6, 14, 37, 22, 2, 0, 0, 1, 1, 7, 23, 93, 146, 68, 2, 0, 0, 1, 1, 8, 32, 203, 602, 772, 166, 2, 0, 0, 1, 1, 9, 46, 399, 2126, 5847, 4449, 534, 2, 0, 0

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OFFSET

0,13

COMMENTS

This sequence may be derived from A333893 by inverse Euler transform.

LINKS

Andrew Howroyd, Table of n, a(n) for n = 0..377 (antidiagonals 0..26)

FORMULA

Column k is the inverse Euler transform of column k of A333893.

EXAMPLE

Array begins:

==============================================

n\k | 0 1 2 3 4 5 6 7

----+-----------------------------------------

0 | 1 1 1 1 1 1 1 1 ...

1 | 1 1 1 1 1 1 1 1 ...

2 | 0 1 2 3 4 5 6 7 ...

3 | 0 0 2 4 9 14 23 32 ...

4 | 0 0 2 12 37 93 203 399 ...

5 | 0 0 2 22 146 602 2126 6308 ...

6 | 0 0 2 68 772 5847 34126 164965 ...

7 | 0 0 2 166 4449 66289 716141 6021463 ...

...

CROSSREFS

Columns k=3..5 are A243391, A289157, A334547.

Main diagonal is A334546.

Cf. A289987, A328682 (regular), A333893 (not necessarily connected).

Sequence in context: A323179 A320508 A164925 * A035671 A190164 A253938

Adjacent sequences: A334543 A334544 A334545 * A334547 A334548 A334549

KEYWORD

nonn,tabl

AUTHOR

Andrew Howroyd, May 05 2020

STATUS

approved