A026918 Sum{T(n-k,k)}, 0<=k<=[ n/2 ], T given by A026907.

1, 13, 41, 90, 185, 335, 601, 1020, 1729, 2857, 4721, 7710, 12593, 20459, 33241, 53880, 87337, 141421, 229001, 370650, 599921, 970823, 1571041, 2542140, 4113505, 6655945, 10769801, 17426070, 28196249, 45622667

Offset: 0

Author

Clark Kimberling

Keywords

• nonn

Links

• Index entries for linear recurrences with constant coefficients, signature (1,3,-2,-3,1,1).

Programs

Mathematica

LinearRecurrence[{1,3,-2,-3,1,1},{1,13,41,90,185,335},30] (* Harvey P. Dale, Jan 08 2015 *)

Formula

8*Fibonacci(n+5) + (3/4)*[(n-1)(-1)^n - 17(n+3)]. - Ralf Stephan, May 13 2004

G.f. ( -1-12*x-25*x^2-12*x^3-x^4 ) / ( (x^2+x-1)*(x-1)^2*(1+x)^2 ). - R. J. Mathar, May 22 2013