A059680 - OEIS

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A059680

Triangle T(n,k) read by rows giving number of fixed 4 X k polyominoes with n cells (n >= 4, 1<=k<=n-3).

6

1, 0, 12, 0, 18, 50, 0, 8, 154, 120, 0, 1, 212, 584, 230, 0, 0, 158, 1396, 1526, 388, 0, 0, 62, 2038, 5154, 3276, 602, 0, 0, 12, 1952, 11328, 14192, 6194, 880, 0, 0, 1, 1232, 17598, 41196, 32824, 10704, 1230, 0, 0, 0, 488, 19912, 87980, 117616, 67284, 17294, 1660

(list; table; graph; refs; listen; history; text; internal format)

OFFSET

4,3

LINKS

Andrew Howroyd, Table of n, a(n) for n = 4..1278

R. C. Read, Contributions to the cell growth problem, Canad. J. Math., 14 (1962), 1-20.

FORMULA

T(n,k) = 0 for n > 4*k. - Andrew Howroyd, Oct 02 2017

EXAMPLE

Triangle starts:

1;

0, 12;

0, 18, 50;

0, 8, 154, 120;

0, 1, 212, 584, 230;

0, 0, 158, 1396, 1526, 388;

0, 0, 62, 2038, 5154, 3276, 602;

0, 0, 12, 1952, 11328, 14192, 6194, 880;

...

CROSSREFS

Column sums are A034187.

Cf. A059678, A059679, A059681, A059684.

Sequence in context: A307163 A254526 A156390 * A307170 A332053 A225951

Adjacent sequences: A059677 A059678 A059679 * A059681 A059682 A059683

KEYWORD

nonn,easy,nice,tabl

AUTHOR

N. J. A. Sloane, Feb 05 2001

EXTENSIONS

Terms a(32) and beyond from Andrew Howroyd, Oct 02 2017

STATUS

approved