Principal diagonal of the convolution array A213781.

Terms

a(0) =1a(1) =7a(2) =19a(3) =41a(4) =72a(5) =118a(6) =176a(7) =254a(8) =347a(9) =465a(10) =601a(11) =767a(12) =954a(13) =1176a(14) =1422a(15) =1708a(16) =2021a(17) =2379a(18) =2767a(19) =3205a(20) =3676a(21) =4202a(22) =4764a(23) =5386a(24) =6047a(25) =6773a(26) =7541a(27) =8379a(28) =9262a(29) =10220