First differences of A007878.

Terms

a(0) =1a(1) =3a(2) =11a(3) =43a(4) =187a(5) =857a(6) =4144a(7) =20812a(8) =107822a(9) =572918a(10) =3108512a(11) =17164308a(12) =96199106a(13) =546137465a(14) =3135381256a(15) =18177991951