OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
MAPLE
V:= Array(-10..10, -10..10): t:=1:
i:= 1: j:= 0: V[0, 0]:= 1: R:= NULL:
do
u:= V[i-1, j]+V[i+1, j]+V[i, j-1]+V[i, j+1];
V[i, j]:= u;
R:= R, $(t+1)..(u-1);
t:= u;
if u > 100 then break fi;
if j > -i and j < i then j:= j+1
elif i > -j and i <= j then i:= i-1
elif i < j and j <= -i then j:= j-1
else i:= i+1
fi;
od:
R; # Robert Israel, May 15 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, May 10 2020
STATUS
approved