a(n)=T(n,3), array T as in A049723.

Terms

a(0) =18a(1) =22a(2) =26a(3) =35a(4) =46a(5) =60a(6) =79a(7) =100a(8) =125a(9) =156a(10) =185a(11) =222a(12) =257a(13) =294a(14) =343a(15) =390a(16) =439a(17) =492a(18) =543a(19) =608a(20) =665a(21) =734a(22) =805a(23) =870a(24) =951a(25) =1026a(26) =1107a(27) =1188a(28) =1275a(29) =1376