Number of length-n strings w over a 4-letter alphabet with the property that if x is a subword of w and |x| >= 2, then x reversed is not a subword of w.
A330011
Number of length-n strings w over a 4-letter alphabet with the property that if x is a subword of w and |x| >= 2, then x reversed is not a subword of w.
Terms
- a(0) =1a(1) =4a(2) =12a(3) =24a(4) =48a(5) =96a(6) =168a(7) =264a(8) =456a(9) =720a(10) =1056a(11) =1656a(12) =2520a(13) =3600a(14) =5352a(15) =7944a(16) =11256a(17) =16248a(18) =23664a(19) =33432a(20) =47520a(21) =68232a(22) =96216a(23) =135696a(24) =192888a(25) =271488a(26) =381384a(27) =538464a(28) =756456a(29) =1060488
External references
- oeis: A330011