Sixth convolution of A115140.

Terms

a(0) =1a(1) =-6a(2) =9a(3) =-2a(4) =0a(5) =0a(6) =-1a(7) =-6a(8) =-27a(9) =-110a(10) =-429a(11) =-1638a(12) =-6188a(13) =-23256a(14) =-87210a(15) =-326876a(16) =-1225785a(17) =-4601610a(18) =-17298645a(19) =-65132550a(20) =-245642760a(21) =-927983760a(22) =-3511574910a(23) =-13309856820a(24) =-50528160150a(25) =-192113383644a(26) =-731508653106