A299017 Intersection of A264041 and A000217.

1, 3, 6, 10, 21, 36, 55, 78, 105, 136, 171, 210, 253, 300, 351

Offset: 1

Author

Colin Barker, Jan 31 2018

Keywords

• nonn
• more

Crossrefs

Cf. A000217, A264041.

Formula

Conjectures (Start)

G.f.: x*(1 + 6*x^4 - 3*x^5) / (1 - x)^3.

a(n) = 6 - 7*n + 2*n^2 for n>3.

a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>3.

(End)