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A338210 Triangle of coefficients of perimeter polynomials for fixed polyominoes. 3
1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 4, 2, 0, 0, 0, 0, 0, 0, 0, 0, 9, 8, 2, 0, 0, 0, 0, 0, 0, 0, 0, 1, 20, 28, 12, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 54, 80, 60, 16, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 22, 136, 252, 228, 100, 20, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,13

COMMENTS

Considered as a triangle, T(n,k) is the number of polyominoes of n cells having a (cell) perimeter of k.

LINKS

Sean A. Irvine, Table of n, a(n) for n = 0..437; rows 0..19 flattened

Sean A. Irvine, Java program (github)

FORMULA

A001168(n) = Sum_{k=0..2*n+2} T(n,k).

EXAMPLE

Polynomials begin:

  1;

  x^4;

  2*x^6;

  4*x^7 + 2*x^8;

  9*x^8 + 8*x^9 + 2*x^10;

  ...

CROSSREFS

Cf. A001168 (row sums), A338211 (free equivalent), A338212 (sprawl), A003203.

Sequence in context: A083929 A182660 A286100 * A122698 A002483 A282530

Adjacent sequences:  A338207 A338208 A338209 * A338211 A338212 A338213

KEYWORD

nonn,tabf

AUTHOR

Sean A. Irvine, Oct 16 2020

STATUS

approved

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Last modified February 26 17:22 EST 2021. Contains 341632 sequences. (Running on oeis4.)