[seqfan] 2 sequences from making triangles out of straws

Neil Sloane njasloane at gmail.com
Tue Nov 15 03:07:15 CET 2016


Dear Seq Fans,  This paper

Sergei Abramovich, <a href="
http://epublications.bond.edu.au/cgi/viewcontent.cgi?article=1187&context=ejsie">Combinatorics
of the Triangle Inequality: From Straws to Experimental Mathematics for
Teachers</a>, Spreadsheets in Education (eJSiE), Vol. 9, Issue 1, Article
1, 2016

gives two sequences that were not in the OEIS.  I have just added them, see
A278036, A278037.  We are in kindergarten, and we are making triangles using
straws of two (or three) colors. The longest side is n. In how many ways
can this be done?  The rules for deciding when two triangles are the same
are not clear to me. Maybe someone could figure out what is going on, and
add more terms?


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