Number of permutations of n copies of 1..3 introduced in order 1..3 with no element equal to another within a distance of 1.
A190917
Number of permutations of n copies of 1..3 introduced in order 1..3 with no element equal to another within a distance of 1.
Terms
- a(0) =1a(1) =1a(2) =5a(3) =29a(4) =182a(5) =1198a(6) =8142a(7) =56620a(8) =400598a(9) =2872754a(10) =20824778a(11) =152303410a(12) =1122149800a(13) =8319825040a(14) =62017475600a(15) =464452683432
External references
- oeis: A190917