Number of ternary words of length n in which all digits 0..2 occur in every subword of 4 consecutive digits.

A248959

Number of ternary words of length n in which all digits 0..2 occur in every subword of 4 consecutive digits.

Terms

    a(0) =1a(1) =3a(2) =9a(3) =27a(4) =36a(5) =72a(6) =132a(7) =240a(8) =444a(9) =816a(10) =1500a(11) =2760a(12) =5076a(13) =9336a(14) =17172a(15) =31584a(16) =58092a(17) =106848a(18) =196524a(19) =361464a(20) =664836a(21) =1222824a(22) =2249124a(23) =4136784a(24) =7608732a(25) =13994640a(26) =25740156a(27) =47343528a(28) =87078324a(29) =160162008

External references