a(n) is the number of configurations of n indistinguishable pairs placed on the vertices of the ladder graph P_2 X P_n such that all but 4 such pairs are joined by an edge.
A318269
a(n) is the number of configurations of n indistinguishable pairs placed on the vertices of the ladder graph P_2 X P_n such that all but 4 such pairs are joined by an edge.
Terms
- a(0) =0a(1) =0a(2) =0a(3) =0a(4) =21a(5) =347a(6) =2919a(7) =17050a(8) =78815a(9) =309075a(10) =1072617a(11) =3386970a(12) =9921030a(13) =27338000a(14) =71614370a(15) =179788174a(16) =435311905a(17) =1021684125a(18) =2333955085a(19) =5207067714a(20) =11377225161a(21) =24403026561a(22) =51484962205a(23) =107024887620a(24) =219528748908a(25) =444886466640a(26) =891735024852
External references
- oeis: A318269