A086406 Main diagonal of number array A086404.

1, 2, 11, 84, 857, 10984, 169803, 3076688, 63968273, 1501465248, 39277112843, 1133193163840, 35748951528681, 1224258310112384, 45233097633685643, 1793524939926112512, 75966131556225961121, 3423203234058532082176

Offset: 0

Author

Paul Barry, Jul 19 2003

Keywords

• easy
• nonn

Crossrefs

Cf. A086352.

Formula

a(n)=(n-sqrt(3))^n(1/2-sqrt(3)/6)+(n+sqrt(3))^n(1/2+sqrt(3)/6)