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 3 such pairs are joined by an edge.
A318268
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 3 such pairs are joined by an edge.
Terms
- a(0) =0a(1) =0a(2) =0a(3) =2a(4) =34a(5) =250a(6) =1234a(7) =4830a(8) =16174a(9) =48444a(10) =133416a(11) =344220a(12) =843020a(13) =1978804a(14) =4484228a(15) =9865742a(16) =21166390a(17) =44439910a(18) =91570126a(19) =185614242a(20) =370846914a(21) =731502296a(22) =1426514540a(23) =2753525208a(24) =5266164280a(25) =9987859912a(26) =18799814312a(27) =35141997050a(28) =65274659562a(29) =120540177522
External references
- oeis: A318268