A095288 Least middle side of 2^n primitive arithmetic triangles, i.e., primitive Heronian triangles whose sides are in arithmetic progression.

4, 28, 364, 6916, 214396, 7932652, 341104036, 20807346196, 1394092195132, 101768730244636, 8039729689326244, 779853779864645668, 80324939326058503804, 8755418386540376914636, 1111938135090627868158772

Offset

0,1

Links

Table of n, a(n) for n=0..14.

Formula

a(n) = A095267(n)/3 = a(n-1) * A002476(n). - Ray Chandler, Jul 09 2004

Example

6916 is the first middle side belonging to 2^3=8 arithmetic triangles, viz., (3485,6916,10347), (3747,6916,10085), (4133,6916,9699), (4299,6916,9533), (4827,6916,9005), (5045,6916,8787), (5333,6916,8499), (6267,6916,7565) of common differences 3431, 3169, 2783, 2617, 2089, 1871, 1583, 649 respectively and integral areas. (Perimeter is obviously three times middle side and hence the same for all the triangles.)

Crossrefs

Cf. A086909.

Sequence in context: A309147 A217903 A339283 * A155105 A132685 A180966

Adjacent sequences: A095285 A095286 A095287 * A095289 A095290 A095291

Keyword

nonn

Author

Lekraj Beedassy, Jul 02 2004

Extensions

More terms from Ray Chandler, Jul 09 2004

Status

approved