Number of tilings of a 5 X n rectangle using n pentominoes of shapes Z, I, P.

Terms

a(0) =1a(1) =1a(2) =3a(3) =7a(4) =17a(5) =78a(6) =195a(7) =616a(8) =1783a(9) =5120a(10) =16714a(11) =48843a(12) =150407a(13) =453178a(14) =1356478a(15) =4174538a(16) =12554221a(17) =38233788a(18) =115868736a(19) =350343710a(20) =1065875246a(21) =3225913135a(22) =9793613873a(23) =29699991965a(24) =90011535049a(25) =273180669975a(26) =828073217940