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A229462
Idoneal numbers (A000926) that are not pentagon exception numbers (A229461).
1
7, 15, 28, 60, 112, 240
OFFSET
1,1
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).
Sequence in context: A193553 A274090 A195041 * A302125 A006188 A198589
KEYWORD
nonn,fini,full
AUTHOR
Suggested by Eike Hertel, Hugo Pfoertner, Sep 24 2013
STATUS
approved