Number of permutations of length n avoiding each length 5 pattern p with p(1)=5 and (p(5)=4 or p(4)=4).

A178594

Number of permutations of length n avoiding each length 5 pattern p with p(1)=5 and (p(5)=4 or p(4)=4).

Terms

    a(0) =0a(1) =1a(2) =2a(3) =6a(4) =24a(5) =108a(6) =516a(7) =2556a(8) =12972a(9) =66996a(10) =350628a(11) =1854252a(12) =9888924a(13) =53107236a(14) =286882740a(15) =1557510012a(16) =8492587596a(17) =46483203348a(18) =255273601860

External references