A203900 a(n)=f(a(n-1)+1,a(n-2),a(n-3)+1), where f(x,y,z)=yz+zx+xy and (a(1),a(2),a(3))=(0,0,1).

0, 0, 1, 2, 7, 36, 391, 17536, 7520303, 134830884224, 1016333764230127711, 137040823237740906153712364032, 139279234211744145176797121311869355242595356863

Offset

1,4

Comments

For a guide to related sequences, see A203761.

Links

Table of n, a(n) for n=1..13.

Mathematica

a[1] = 0; a[2] = 0; a[3] = 1;
a[n_] := SymmetricPolynomial[2, {1 + a[n - 1], a[n - 2], 1 + a[n - 3]}]
Table[a[n], {n, 1, 16}]  (* A203900 *)

Crossrefs

Cf. A203761.

Sequence in context: A002724 A348106 A292206 * A209251 A366670 A368398

Adjacent sequences: A203897 A203898 A203899 * A203901 A203902 A203903

Keyword

nonn

Author

Clark Kimberling, Jan 07 2012

Status

approved