Triangle read by rows giving number of arrangements of k dumbbells on 2 X n grid (n >= 0, k >= 0).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =4a(5) =2a(6) =1a(7) =7a(8) =11a(9) =3a(10) =1a(11) =10a(12) =29a(13) =26a(14) =5a(15) =1a(16) =13a(17) =56a(18) =94a(19) =56a(20) =8a(21) =1a(22) =16a(23) =92a(24) =234a(25) =263a(26) =114a(27) =13a(28) =1a(29) =19