A331775 a(n) = Sum_{-n<i<n, -n<j<n, gcd{i,j}=3} (n-|i|)*(n-|j|)/4.

0, 0, 0, 5, 14, 27, 52, 85, 126, 197, 284, 387, 534, 705, 900, 1187, 1514, 1881, 2328, 2823, 3366, 4095, 4896, 5769, 6818, 7955, 9180, 10667, 12266, 13977, 15928, 18007, 20214, 22899, 25752, 28773, 32114, 35639, 39348, 43733, 48350, 53199, 58544

Offset

1,4

Links

Table of n, a(n) for n=1..43.

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.

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)/4, n=1..50)];

Crossrefs

This is A177720/2 and A331774/4.

Sequence in context: A375291 A014106 A110325 * A140342 A055454 A301294

Adjacent sequences: A331772 A331773 A331774 * A331776 A331777 A331778

Keyword

nonn

Author

N. J. A. Sloane, Feb 08 2020

Status

approved