Number of n-color compositions of n having at least one pair of adjacent parts that are the same color.

A374925

Number of n-color compositions of n having at least one pair of adjacent parts that are the same color.

Terms

    a(0) =0a(1) =0a(2) =1a(3) =3a(4) =10a(5) =31a(6) =91a(7) =259a(8) =726a(9) =2007a(10) =5489a(11) =14888a(12) =40122a(13) =107574a(14) =287239a(15) =764405a(16) =2028679a(17) =5371858a(18) =14198008a(19) =37467982a(20) =98749767a(21) =259984452a(22) =683865318a(23) =1797500121a(24) =4721662597a(25) =12396308875a(26) =32531025970a(27) =85337831350a(28) =223794544179a(29) =586736215856

External references