%I #15 Oct 29 2020 18:49:13
%S 3,9,7,123,1773,21075,68761,4989753,178945525,396450465051,
%T 144693391952079,4833128874789907,751463705427149325,
%U 59315127102256318272081,30288529373611329886681,335082000330404529286853990499,6485606445639875637410148108213,7842015457241561891262053489240216057
%N a(n) is the denominator of the resistance R(n) = A338401(n)/a(n) of a triangular network of 3*n*(n+1)/2 one Ohm resistors in a hexagonal lattice arrangement.
%C For more information and example see A338401.
%H Hugo Pfoertner, <a href="/A338402/b338402.txt">Table of n, a(n) for n = 1..50</a>
%Y Cf. A338401.
%K nonn,frac
%O 1,1
%A _Hugo Pfoertner_, Oct 24 2020