A355586 - OEIS

%I #7 Jul 22 2022 16:44:25

%S 1,3,3,3,1,1,3,1,1,3,3,1,1,3,3,1,3,3,1,3,3,3,3,3,3,1,1,1,1,1,3,1,1,1,

%T 1,1,3,3,1,1,1,1,1,3,3,1,1,1,1,3,3,1,3,1,1,1,3,3,3,3,3,1,1,1,1,1,1,1,

%U 3,3,1,1,3,1,1,1,3,1,3,1,1,3,3,1,1,3,3,3,3,1

%N T(j,k) are the denominators t in the representation R = s/t + (2*sqrt(3)/Pi)*u/v of the resistance between two nodes separated by the distance (j,k) in an infinite triangular lattice of one-ohm resistors, where T(j,k), j >= 0, 0 <= k <= floor(j/2) is an irregular triangle read by rows.

%C See A355585 for more information.

%D See A211074 for references and links.

%e The triangle begins:

%e   1;

%e   3;

%e   3, 3;

%e   1, 1;

%e   3, 1, 1;

%e   3, 3, 1;

%e   1, 3, 3, 1;

%e   3, 3, 1, 3;

%e   3, 3, 3, 3, 3;

%e   1, 1, 1, 1, 1;

%o (PARI) See A355585.

%Y A355585 are the corresponding numerators.

%Y A355587 and A355588 are u and v.

%K nonn,tabf,frac

%O 0,2

%A _Hugo Pfoertner_, Jul 09 2022