Number of permutations of length n containing exactly 3 occurrences of 123 and 3 occurrences of 132.

A224290

Number of permutations of length n containing exactly 3 occurrences of 123 and 3 occurrences of 132.

Terms

    a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =1a(6) =6a(7) =30a(8) =136a(9) =566a(10) =2176a(11) =7808a(12) =26440a(13) =85332a(14) =264632a(15) =793792a(16) =2315136a(17) =6592640a(18) =18390784a(19) =50392064a(20) =135921664a(21) =361536512a(22) =949708800a(23) =2466807808a(24) =6342115328a(25) =16153509888a(26) =40790523904a(27) =102186352640a(28) =254105092096a(29) =627533152256

External references