Number of tilings of a 4 X n rectangle with n tetrominoes of any shape.

A174248

Number of tilings of a 4 X n rectangle with n tetrominoes of any shape.

Terms

    a(0) =1a(1) =1a(2) =4a(3) =23a(4) =117a(5) =454a(6) =2003a(7) =9157a(8) =40899a(9) =179399a(10) =796558a(11) =3546996a(12) =15747348a(13) =69834517a(14) =310058192a(15) =1376868145a(16) =6112247118a(17) =27132236455a(18) =120453362938a(19) =534754586459

External references