A331774 a(n) = Sum_{-n

0, 0, 0, 20, 56, 108, 208, 340, 504, 788, 1136, 1548, 2136, 2820, 3600, 4748, 6056, 7524, 9312, 11292, 13464, 16380, 19584, 23076, 27272, 31820, 36720, 42668, 49064, 55908, 63712, 72028, 80856, 91596, 103008, 115092, 128456, 142556, 157392, 174932, 193400

Offset: 1

Author

N. J. A. Sloane, Feb 08 2020

Keywords

• nonn

Links

• M. A. Alekseyev, M. Basova, and N. Yu. Zolotykh. On the minimal teaching sets of two-dimensional threshold functions. SIAM Journal on Discrete Mathematics 29:1 (2015), 157-165. doi:10.1137/140978090. See p. 158.

Crossrefs

This is twice A177720 and 4 times A331775.

Programs

Maple

VR := proc(m,n,q) local a,i,j; a:=0;
for i from -m+1 to m-1 do for j from -n+1 to n-1 do
if gcd(i,j)=q then a:=a+(m-abs(i))*(n-abs(j)); fi; od: od: a; end;
[seq(VR(n,n,3),n=1..50)];