OFFSET
1,1
EXAMPLE
a(1)=3 since you cannot pack more than 3 unit-side squares in an ellipse of semiaxes 1,2
MATHEMATICA
f[n_] := 2 Sum[IntegerPart[2 Sqrt[4 n^2 - (h - 1/2)^2]],
{h, 2, 2 n}] + IntegerPart[2 Sqrt[4 n^2 - 1/4]]; Array[f, 42]
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Pasquale CUTOLO (p.cutolo(AT)inwind.it), Jun 14 2007
STATUS
approved