a(n) = (2^(3*n + 3 + (-1)^n) - (6 + (-1)^n))/9, for n >= 1.

A350053

a(n) = (2^(3*n + 3 + (-1)^n) - (6 + (-1)^n))/9, for n >= 1.

Terms

    a(0) =3a(1) =113a(2) =227a(3) =7281a(4) =14563a(5) =466033a(6) =932067a(7) =29826161a(8) =59652323a(9) =1908874353a(10) =3817748707a(11) =122167958641a(12) =244335917283

External references