Principal diagonal of the convolution array A213825.

Terms

a(0) =2a(1) =34a(2) =132a(3) =332a(4) =670a(5) =1182a(6) =1904a(7) =2872a(8) =4122a(9) =5690a(10) =7612a(11) =9924a(12) =12662a(13) =15862a(14) =19560a(15) =23792a(16) =28594a(17) =34002a(18) =40052a(19) =46780a(20) =54222a(21) =62414a(22) =71392a(23) =81192a(24) =91850a(25) =103402a(26) =115884a(27) =129332a(28) =143782a(29) =159270