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A056842 Number of polydrafters: a(n) is the number of polydrafters with n cells. See the Paterson link for the definition. 3
1, 6, 14, 64, 237, 1024, 4254, 18664, 81865 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Restatement of the definition: A polydrafter is a polygon formed by joining 30-60-90 triangles, according to the following rules:

(a) Two triangles may be joined along their short legs, with their right angles touching;

(b) Two triangles may be joined along their long legs, with their right angles touching;

(c) Two triangles may be joined along their hypotenuses, in either direction;

(d) The short leg of triangle 1 may be joined to half of the hypotenuse of triangle 2, with the right angle of triangle 1 touching the midpoint of the hypotenuse of triangle 2.

REFERENCES

Ed Pegg, Jr., Polyform puzzles, in Tribute to a Mathemagician, Peters, 2005, pp. 119-125.

LINKS

Table of n, a(n) for n=1..9.

D. Paterson, Pentominos & Dodecadudes

M. Vicher, Polyforms

M. Vicher, Tridrafters

Eric Weisstein's World of Mathematics, Polydrafter.

EXAMPLE

a(3) = 14 because there are 14 tridafters. The second Vicher link shows various arrangements of them.

CROSSREFS

Sequence in context: A032404 A059954 A139257 * A182752 A200033 A219376

Adjacent sequences:  A056839 A056840 A056841 * A056843 A056844 A056845

KEYWORD

nonn,more

AUTHOR

James A. Sellers, Aug 28 2000

EXTENSIONS

Edited by David Wasserman, Dec 01 2003

STATUS

approved

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Last modified December 19 23:11 EST 2014. Contains 252240 sequences.