Number of primitive (aperiodic) word structures of length n using a 4-ary alphabet.

A056275

Number of primitive (aperiodic) word structures of length n using a 4-ary alphabet.

Terms

    a(0) =1a(1) =1a(2) =4a(3) =13a(4) =50a(5) =181a(6) =714a(7) =2780a(8) =11046a(9) =43895a(10) =175274a(11) =699875a(12) =2798250a(13) =11188191a(14) =44747380a(15) =178970560a(16) =715860650a(17) =2863365834a(18) =11453377194a(19) =45813202675a(20) =183252461532a(21) =733008625151

External references