The Numbers a2 + b2 − dc2
Andrzej Nowicki
Nicolaus Copernicus University
Faculty of Mathematics and Computer Science
87-100 Toruń
Poland
Abstract:
We say that a positive integer d is special if for every integer
m
there exist nonzero integers a, b, c such that
m = a2 + b2 − dc2.
In
this note we present examples and some properties of special numbers.
Moreover, we present an infinite sequence of special numbers.
Full version: pdf,
dvi,
ps,
latex
(Concerned with sequences
A000217
A001110.)
Received November 18 2014; revised versions received December 16 2014;
December 18 2014.
Published in Journal of Integer Sequences,
January 24 2015.
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