a(n) = T(3n,n), where T is the array in A026300.

A026303

a(n) = T(3n,n), where T is the array in A026300.

Terms

    a(0) =1a(1) =3a(2) =20a(3) =147a(4) =1143a(5) =9163a(6) =74919a(7) =621015a(8) =5199909a(9) =43878315a(10) =372530781a(11) =3178551148a(12) =27231924300a(13) =234113134518

External references