Number of length-n sequences A over {1,2,3} with the property that all of r(A), r(r(A)), etc. are over {1,2,3}, where r is the sequence obtained by taking the run lengths in A.
A181047
Number of length-n sequences A over {1,2,3} with the property that all of r(A), r(r(A)), etc. are over {1,2,3}, where r is the sequence obtained by taking the run lengths in A.
Terms
- a(0) =1a(1) =3a(2) =9a(3) =27a(4) =54a(5) =180a(6) =426a(7) =1080a(8) =2724a(9) =6300a(10) =16512a(11) =42432a(12) =98064a(13) =248256a(14) =616656a(15) =1509888a(16) =3767040a(17) =9389376a(18) =23549376a(19) =58493760a(20) =140807232a(21) =336314880a(22) =806979456
External references
- oeis: A181047