The number of words of length n created with the letters a, b, c with at least as many a's as b's and at least as many b's as c's and no adjacent letters forming the pattern aba.

A176354

The number of words of length n created with the letters a, b, c with at least as many a's as b's and at least as many b's as c's and no adjacent letters forming the pattern aba.

Terms

    a(0) =1a(1) =1a(2) =3a(3) =9a(4) =17a(5) =46a(6) =153a(7) =338a(8) =935a(9) =3067a(10) =7182a(11) =20064a(12) =64819a(13) =156968a(14) =441084a(15) =1408612a(16) =3488489a(17) =9840608a(18) =31145791a(19) =78388512a(20) =221722954a(21) =696757333a(22) =1775204952a(23) =5031253931a(24) =15718503073a(25) =40435757688a(26) =114779701466a(27) =356852697226a(28) =925209496348

External references