Number of words, either empty or beginning with the first letter of the n-ary alphabet, where each letter of the alphabet occurs 3 times and letters of neighboring word positions are equal or neighbors in the alphabet.
A208674
Number of words, either empty or beginning with the first letter of the n-ary alphabet, where each letter of the alphabet occurs 3 times and letters of neighboring word positions are equal or neighbors in the alphabet.
Terms
- a(0) =1a(1) =1a(2) =10a(3) =37a(4) =163a(5) =640a(6) =2503a(7) =9559a(8) =36154a(9) =135541a(10) =505279a(11) =1875592a(12) =6941035a(13) =25629211a(14) =94478338a(15) =347857921a(16) =1279622611a(17) =4704064120a(18) =17284247263a(19) =63484653151a(20) =233114307274a(21) =855817783741
External references
- oeis: A208674