Catalogue of Blunt Polytans

A polytan or polyabolo is a figure made of equal isosceles right triangles joined along equal edges. A blunt polytan is one that has no 45° interior angles (sharp corners). Here I show all the blunt polytans with up to 9 cells.

Two-sided polytans may be rotated and reflected. One-sided polytans may be rotated but not reflected.

Enumeration

Cells	Two-Sided A305606	One-Sided
1	0	0
2	1	1
3	0	0
4	2	2
5	2	2
6	5	6
7	6	10
8	23	38
9	45	84
10	138	252
11	347	675
12	1007	1954
13	2751	5455
14	7998	15829

The enumerations for arbitrary polyaboloes are in the On-Line Encyclopedia of Integer Sequences as A006074 (two-sided) and A151519 (one-sided).

The figures below show two-sided polytans.

Ditans

Tetratans

Pentatans

Hexatans

Heptatans

Octatans

Enneatans

Last revised 2017-11-25.

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Col. George Sicherman [ HOME | MAIL ]