A203772 a(n)=f(a(n-1),a(n-2)+1,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, 3, 11, 74, 1232, 108084, 141466347, 15464951390151, 2189441739723579832963, 33859919808724254529558716855414396, 74134322256556148244446056491575979484293791968668948464

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, {a[n - 1], 1 + a[n - 2], 1 + a[n - 3]}]
Table[a[n], {n, 1, 14}]  (* A203772 *)

Crossrefs

Cf. A203761.

Sequence in context: A054461 A342433 A374533 * A290025 A239658 A181388

Adjacent sequences: A203769 A203770 A203771 * A203773 A203774 A203775

Keyword

nonn

Author

Clark Kimberling, Jan 07 2012

Status

approved