A027210 a(n) = Sum_{k=0..n-3} T(n,k) * T(n,k+3), with T given by A026725.

1, 9, 57, 298, 1545, 7126, 34603, 151633, 714481, 3049328, 14131926, 59385159, 272409611, 1133433579, 5163641033, 21341122875, 96751092786, 397978832144, 1797722306693, 7369285976135, 33195299823112, 135723491400062, 610027809595308, 2489247495517382, 11168400384253936

Offset: 3

Author

Clark Kimberling

Keywords

• nonn

Programs

Maple

A027210 := proc(n)
    add( A026725(n,k)*A026725(n,k+3),k=0..n-3) ;
end proc: # R. J. Mathar, Oct 21 2019

Extensions

Name corrected by R. J. Mathar, Oct 21 2019

More terms from Sean A. Irvine, Oct 24 2019