A109743 a(2)=1; for n>2, a(n) = A109742(n)/3.

1, 3, 9, 41, 231, 1551, 12037, 105861, 1039539, 11268059, 133585089, 1718984673, 23857531519, 355190381031, 5646040979901, 95432906354621, 1709068974897867, 32325104169244851, 643869687410800249, 13471540400560532889, 295384662114697463319

Offset

2,2

Links

Table of n, a(n) for n=2..22.

Crossrefs

Cf. A000166, A109742.

Sequence in context: A012099 A159039 A074502 * A139150 A360704 A293955

Adjacent sequences: A109740 A109741 A109742 * A109744 A109745 A109746

Keyword

nonn

Author

N. J. A. Sloane, Aug 13 2005

Status

approved