%I
%S 1,0,4,12,56,280,1488,8232,47008,274824,1636520,9890584,60510480,
%T 374019776,2332131872,14651535840,92653845120,589317728376,
%U 3767523372432,24196006128592,156030800105840
%N Cycle class sequence c(2n) (the number of true cycles of length 2n in which a certain node is included) for square lattice.
%D G. Thimm and W. E. Klee, Zeolite cycle sequences, Zeolites, 19, pp. 422424, 1997.
%H G. Thimm, <a href="/thimm1.html">Cycle sequences of crystal structures</a>
%t (Length@FindCycle[{NearestNeighborGraph[Tuples[Range[2 # + 4], 2], {All, 1.}], {#+2,#+2}}, {2 #}, All]) & /@ Range[11] (* _Gabriel B. Apolinario_, Jan 07 2017 *)
%K nonn,more
%O 0,3
%A Georg Thimm (mgeorg(AT)ntu.edu.sg)
%E a(11) from _Gabriel B. Apolinario_, Jan 07 2017
%E a(12)a(18) from _Aleksandr D. Krotov_, Jan 07 2018
%E a(19)a(20) from _Aleksandr D. Krotov_, Mar 22 2019
