Number of words of length n composed of the letters a, b, and c with at least as many a's as b's, and at least as many b's as c's, and no a's adjacent.
A174247
Number of words of length n composed of the letters a, b, and c with at least as many a's as b's, and at least as many b's as c's, and no a's adjacent.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =7a(4) =9a(5) =21a(6) =76a(7) =104a(8) =255a(9) =936a(10) =1321a(11) =3327a(12) =12250a(13) =17682a(14) =45200a(15) =166420a(16) =244431a(17) =630586a(18) =2318863a(19) =3453662a(20) =8964527a(21) =32909250a(22) =49579091a(23) =129250365a(24) =473604092a(25) =720390529a(26) =1884080667a(27) =6890849851a(28) =10567693128a(29) =27706723888
External references
- oeis: A174247