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A338213 a(n) is the number of free polyominoes with sprawl n. 3


%S 1,0,0,0,0,1,0,0,1,0,1,1,3,2,4,6,13,15,30,50,93,158,287,513,950,1735,

%T 3212,5945,11099,20720,38910,73002,137821,259757

%N a(n) is the number of free polyominoes with sprawl n.

%C The sprawl of a polyomino is the number of cells in a polyomino plus the number of cells adjacent to it.

%H Sean A. Irvine, <a href="https://github.com/archmageirvine/joeis/blob/master/src/irvine/oeis/a338/A338213.java">Java program</a> (github)

%F Antidiagonal sums of A338211.

%Y Cf. A000105, A338211, A338212.

%K nonn,more

%O 0,13

%A _Sean A. Irvine_ and _Allan C. Wechsler_, Oct 17 2020

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Last modified April 22 22:01 EDT 2021. Contains 343189 sequences. (Running on oeis4.)