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A070765 Number of polyiamonds with n cells, without holes. 6
1, 1, 1, 3, 4, 12, 24, 66, 159, 444, 1161, 3226, 8785, 24453, 67716, 189309, 528922, 1484738, 4172185, 11756354, 33174451, 93795220, 265565628, 753060469, 2138206966, 6078931114, 17302380313, 49302121747, 140627400927, 401510058179 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

If holes are allowed, we get A000577.

REFERENCES

E. V. Konstantinova and M. V. Vidyuk, Discriminating tests of information and topological indices; animals and trees; J. Chem. Inf. Comput. Sci., 43 (2003), 1860-1871.

LINKS

Table of n, a(n) for n=1..30.

CROSSREFS

Equals A000577(n)-A070764(n). Cf. A000104, A018190.

Sequence in context: A073713 A291023 A084921 * A000577 A111758 A264484

Adjacent sequences:  A070762 A070763 A070764 * A070766 A070767 A070768

KEYWORD

hard,nonn

AUTHOR

Joseph Myers, May 05 2002

EXTENSIONS

More terms from Joseph Myers, Nov 11 2003

a(29) and a(30) from Joseph Myers, Nov 21 2010

STATUS

approved

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Last modified December 10 04:14 EST 2019. Contains 329885 sequences. (Running on oeis4.)