A356975 a(n) is the number of n-celled pseudo-polyominoes with holes.

0, 0, 0, 1, 3, 28, 199, 1603, 12234, 93270, 697641, 5167477, 37913465

Offset: 1

Author

John Mason, Sep 07 2022

Keywords

• nonn
• hard
• more

Examples

			a(4)=1 because of:
   O
  O O
   O
a(5)=3 because of:
   O    O     O
  O O  O OO  O O
  OO    O     O O
		

Crossrefs

Cf. A030222, A001419.