Let S denote the palindromes in the language {0,1,2}*; a(n) = number of words of length n in the language SS.

A007056

Let S denote the palindromes in the language {0,1,2}*; a(n) = number of words of length n in the language SS.

Terms

    a(0) =1a(1) =3a(2) =9a(3) =21a(4) =57a(5) =123a(6) =279a(7) =549a(8) =1209a(9) =2127a(10) =4689a(11) =7989a(12) =17031a(13) =28395a(14) =60615a(15) =98061a(16) =208569a(17) =334563a(18) =705789a(19) =1121877a(20) =2356737a(21) =3718827a(22) =7786359a(23) =12223077a(24) =25488903a(25) =39857523a(26) =82876257a(27) =129135729a(28) =267784119a(29) =416118219

External references