Number of 2n-bead necklaces labeled with numbers 1..5 not allowing reversal, with neighbors differing by exactly 1.

A208724

Number of 2n-bead necklaces labeled with numbers 1..5 not allowing reversal, with neighbors differing by exactly 1.

Terms

    a(0) =4a(1) =7a(2) =12a(3) =25a(4) =52a(5) =131a(6) =316a(7) =835a(8) =2196a(9) =5935a(10) =16108a(11) =44369a(12) =122644a(13) =341803a(14) =956636a(15) =2690845a(16) =7596484a(17) =21524543a(18) =61171660a(19) =174342217a(20) =498112276a(21) =1426419859a(22) =4093181692a(23) =11767920119a(24) =33891544420a(25) =97764131647a(26) =282429537948a(27) =817028472961

External references