A229462 Idoneal numbers (A000926) that are not pentagon exception numbers (A229461).

7, 15, 28, 60, 112, 240

Offset: 1

Author

Suggested by Eike Hertel, Hugo Pfoertner, Sep 24 2013

Keywords

• nonn
• fini
• full

Comments

See A229461.

Idoneal numbers not of the form 7 or 15 times a square. - Hugo Pfoertner, Aug 13 2017

Links

• Eike Hertel, Reguläre Dreieckspflasterungen konvexer Polygone, Jenaer Schriften zur Mathematik und Informatik Math/Inf/01/13, 2013 (Preprint).
• Eike Hertel, Christian Richter, Tiling Convex Polygons with Congruent Equilateral Triangles, Discrete Comput Geom (2014) 51:753-759.
• MathOverflow, Which natural numbers are a square minus a sum of two squares?. Answer by user "Lucia", 2014 Dec 5.

Crossrefs

Cf. A000926 (idoneal numbers), A229461 (pentagon exception numbers).