A094166 Array read by antidiagonals: T(n,k) = number of rooted 2-dimensional polyominoes with k cells, the cells being regular n-gons, with no symmetries removed.

1, 1, 3, 1, 4, 9, 1, 5, 18, 28, 1, 6, 30, 76, 90, 1, 7, 33, 180, 315, 282, 1, 8, 42, 176, 1075, 1296, 875, 1, 9, 60, 252, 930, 6366, 5320, 2700, 1, 10, 81, 440, 1505, 4884, 37520, 21800, 8271, 1, 11, 105, 732, 3230, 8946, 25564, 220500, 89190, 25265

Offset

1,3

References

Dan Hoey, Bill Gosper and Richard C. Schroeppel, Discussions in Math-Fun Mailing list, circa Jul 13 1999.

Links

Table of n, a(n) for n=1..55.

R. C. Schroeppel, A few mathematical experiments [Broken link?]

R. C. Schroeppel, A few mathematical experiments

R. C. Schroeppel, A few mathematical experiments [Cached copy - permission requested]

Example

Array begins:
1 3 9 28 90 282 875 2700 8271 25265 ...
1 4 18 76 315 1296 5320 21800 89190 364460 ...
1 5 30 180 1075 6366 37520 220500 1293615 7581240 ...
1 6 33 176 930 4884 25564 133512 696231 3626710 ...
1 7 42 252 1505 8946 53165 315980 1878597 11171930 ...
1 8 60 440 3230 23688 173796 1275240 9359748 68708320 ...
1 9 81 732 6660 60534 549801 4991436 45301356 411062595 ...
1 10 105 1080 11060 112932 1151430 11728960 119405565 1215105280 ...
1 11 132 1584 18920 225258 2677675 31805400 377611443 4481810410 ...
1 12 138 1564 17655 198936 2239860 25209144 283667850 3191677980 ...
1 13 156 1872 22425 268398 3212391 38454000 460400148 5513163565 ...
1 14 189 2520 33530 445788 5925976 78775480 1047251079 13923394730 ...

Crossrefs

Rows give A094164, A048664, A051738, A094165, A094168, A094169.

Sequence in context: A122115 A049916 A220605 * A266131 A338871 A202353

Adjacent sequences: A094163 A094164 A094165 * A094167 A094168 A094169

Keyword

nonn,tabl,easy

Author

N. J. A. Sloane, May 06 2004

Extensions

More terms from Joshua Zucker, May 20 2006

Status

approved