Main diagonal of the square array A058395.

Terms

a(0) =1a(1) =1a(2) =4a(3) =10a(4) =25a(5) =61a(6) =146a(7) =344a(8) =800a(9) =1840a(10) =4192a(11) =9472a(12) =21248a(13) =47360a(14) =104960a(15) =231424a(16) =507904a(17) =1110016a(18) =2416640a(19) =5242880a(20) =11337728a(21) =24444928a(22) =52559872a(23) =112721920a(24) =241172480a(25) =514850816a(26) =1096810496a(27) =2332033024a(28) =4949278720a(29) =10485760000