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 bba.
A204340
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 bba.
Terms
- a(0) =1a(1) =1a(2) =3a(3) =10a(4) =21a(5) =57a(6) =182a(7) =426a(8) =1167a(9) =3679a(10) =8991a(11) =24873a(12) =77492a(13) =194449a(14) =541194a(15) =1670783a(16) =4267991a(17) =11926782a(18) =36559601a(19) =94604822a(20) =265135713a(21) =808106960a(22) =2111760491a(23) =5931204471a(24) =17993213402a(25) =47385794268a(26) =133315710843a(27) =402849979395
External references
- oeis: A204340