Number of permutations of length n containing exactly 4 occurrences of 123 and 4 occurrences of 132.

A224291

Number of permutations of length n containing exactly 4 occurrences of 123 and 4 occurrences of 132.

Terms

    a(0) =0a(1) =0a(2) =0a(3) =0a(4) =1a(5) =11a(6) =60a(7) =270a(8) =1084a(9) =4028a(10) =14144a(11) =47577a(12) =154740a(13) =489728a(14) =1514786a(15) =4593118a(16) =13682374a(17) =40106060a(18) =115824376a(19) =329901232a(20) =927585696a(21) =2576685888a(22) =7076644480a(23) =19228648192a(24) =51725149184

External references