Number of 3-matchings of the n X n grid graph.

Terms

a(0) =0a(1) =0a(2) =0a(3) =56a(4) =1044a(5) =6632a(6) =26172a(7) =78536a(8) =196916a(9) =434584a(10) =871612a(11) =1622552a(12) =2845076a(13) =4749576a(14) =7609724a(15) =11773992a(16) =17678132a(17) =25858616a(18) =36967036a(19) =51785464a(20) =71242772a(21) =96431912a(22) =128628156a(23) =169308296a(24) =220170804a(25) =283156952a(26) =360472892a(27) =454612696a(28) =568382356a(29) =704924744