Number of permutations of [n] that require a 3-letter alphabet in order to be realized by a shift.

A192089

Number of permutations of [n] that require a 3-letter alphabet in order to be realized by a shift.

Terms

    a(0) =0a(1) =0a(2) =6a(3) =66a(4) =402a(5) =2028a(6) =8790a(7) =35118a(8) =131982a(9) =475344a(10) =1658382a(11) =5651226a(12) =18912498a(13) =62418180a(14) =203768862a(15) =659487678a(16) =2119617474a(17) =6774043254a(18) =21547968726a(19) =68274910026a(20) =215609878962a(21) =678936947940

External references