Sixth convolution of Lucas numbers A000032(n+1), n >= 0.

Terms

a(0) =1a(1) =21a(2) =217a(3) =1498a(4) =7910a(5) =34566a(6) =131446a(7) =449732a(8) =1416513a(9) =4174765a(10) =11651717a(11) =31075422a(12) =79751854a(13) =198036146a(14) =477899790a(15) =1124785648a(16) =2589534248a(17) =5845989156a(18) =12968091584a(19) =28316428700a(20) =60953528230a(21) =129515454530a(22) =271955244610a(23) =564879359940