an interesting new sequence!

[Robert G. Wilson v]

Neil,

	He is only counting the smaller triangles. When you go to the hyper-links you 
will see that there are other "super" triangles - triangles made by two or more 
smaller triangles. a(5) would then equal 8 and a(6) would then be 13.

Bob.

N. J. A. Sloane wrote:

> This just came in - at first I rejected it,
> thinking it was the same as A000124.  But it isn't!
> 
> Can it really be new?
> 
> NJAS
> 
> %I A107427
> %S A107427 0,0,1,2,4,7,10,14,18,22,27,32,38,44,50,54,60,72,76,84,92,110,114,122,
> %T A107427 130,156,160,210
> %N A107427 Maximal number of triangles that can be formed by n straight lines in the Euclidian plane.
> %C A107427 A000124 is a related sequence, but that sequence refers to regions whereas here we only consider triangles.
> %H A107427 David Coles, <a href="http://davcoles.tripod.com">Triangle Puzzle</a>.
> %H A107427 Jim Loy, <a href="http://www.jimloy.com/puzz/cole.htm">Triangle Puzzle</a>.
> %e A107427 7 lines can make at most 10 triangles, so a(7) = 10.
> %Y A107427 Cf. A000124.
> %K A107427 nonn,nice,more,new
> %O A107427 1,4
> %A A107427 Bill Blewett (billble(AT)comcast.net), May 22 2005
>