A026397 Sum{T(n-k,k)}, 0<=k<=[ n/2 ], where T is the array in A026386.

1, 2, 3, 6, 10, 17, 31, 53, 92, 163, 282, 492, 863, 1501, 2621, 4582, 7987, 13946, 24354, 42489, 74179, 129497, 226000, 394523, 688670, 1202020, 2098239, 3662553, 6392969, 11159290, 19478867, 34000750, 59349706, 103596641

Offset: 0

Author

Clark Kimberling

Keywords

• nonn

Links

• Index entries for linear recurrences with constant coefficients, signature (0,1,3,1).

Programs

Mathematica

LinearRecurrence[{0,1,3,1},{1,2,3,6},40] (* Harvey P. Dale, Apr 15 2015 *)

Formula

Pairwise sums of A026385. - Ralf Stephan, Jul 22 2003

G.f.: [(1+x)(1+x+x^2)]/[1-x^2-3x^3-x^4]. - Ralf Stephan, Apr 30 2004