a(n) = [ (2n+1)/(n-1) ] + [ (2n+2)/(n-2) ] + ... + [ (3n-1)/1 ].

Terms

a(0) =5a(1) =11a(2) =19a(3) =26a(4) =35a(5) =44a(6) =54a(7) =62a(8) =74a(9) =83a(10) =96a(11) =103a(12) =117a(13) =128a(14) =140a(15) =150a(16) =162a(17) =175a(18) =189a(19) =198a(20) =213a(21) =222a(22) =240a(23) =249a(24) =263a(25) =277a(26) =291a(27) =300a(28) =318a(29) =329