OFFSET
1,2
COMMENTS
This is A004018 with the zero terms omitted.
LINKS
T. D. Noe, Table of n, a(n) for n = 1..10000
EXAMPLE
a(1) = 1 from (0, 0).
a(2) = 4 from (0, 1), (0, -1), (1, 0), (-1, 0).
a(5) = 8 from (+-1, +-2), (+-2, +-1).
MATHEMATICA
max = 100; A001481 = Select[Range[0, 4*max], SquaresR[2, #] != 0 &]; A004018[n_] := SquaresR[2, n]; a[n_] := A004018[A001481[[n]]]; Table[a[n], {n, 1, max}] (* Jean-François Alcover, Oct 04 2013, after Franz Vrabec *)
CROSSREFS
KEYWORD
nice,nonn
AUTHOR
Sébastien Dumortier, Apr 30 2005
EXTENSIONS
Definition revised by N. J. A. Sloane, Oct 04 2013
STATUS
approved