Number of words either empty or beginning with the first letter of the cyclic n-ary alphabet, where each letter of the alphabet occurs twice and letters of neighboring word positions are equal or neighbors in the alphabet.
A208880
Number of words either empty or beginning with the first letter of the cyclic n-ary alphabet, where each letter of the alphabet occurs twice and letters of neighboring word positions are equal or neighbors in the alphabet.
Terms
- a(0) =1a(1) =1a(2) =3a(3) =30a(4) =62a(5) =114a(6) =202a(7) =346a(8) =582a(9) =966a(10) =1590a(11) =2602a(12) =4242a(13) =6898a(14) =11198a(15) =18158a(16) =29422a(17) =47650a(18) =77146a(19) =124874a(20) =202102a(21) =327062a(22) =529254a(23) =856410a(24) =1385762a(25) =2242274a(26) =3628142a(27) =5870526a(28) =9498782a(29) =15369426
External references
- oeis: A208880