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A057729 Number of triangular polyominoes (or polyiamonds) [A000577] with perimeter n. 8
0, 0, 1, 1, 1, 4, 5, 16, 37, 120, 345, 1179 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

REFERENCES

a(10) found by Brendan Owen.

LINKS

Table of n, a(n) for n=1..12.

Andrew Clarke, Isometrical Polyiamonds

Picture from Andrew Clarke's page showing the 4 polyiamonds of perimeter 6 and the 5 of perimeter 7.

CROSSREFS

Cf. A000577, A284869, A316196.

Sequence in context: A196021 A064294 A284869 * A110278 A013628 A127007

Adjacent sequences:  A057726 A057727 A057728 * A057730 A057731 A057732

KEYWORD

nonn,nice,more

AUTHOR

N. J. A. Sloane, Oct 29 2000

EXTENSIONS

Link updated by William Rex Marshall, Dec 16 2009

a(11)-a(12) from Luca Petrone, Apr 04 2017

STATUS

approved

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Last modified January 29 14:07 EST 2020. Contains 331338 sequences. (Running on oeis4.)