a(n) = (1/2)*(n-th largest even number in array T given by A027170).

Terms

a(0) =5a(1) =15a(2) =21a(3) =29a(4) =38a(5) =47a(6) =69a(7) =78a(8) =95a(9) =125a(10) =132a(11) =159a(12) =181a(13) =197a(14) =236a(15) =239a(16) =285a(17) =335a(18) =370a(19) =389a(20) =395a(21) =447a(22) =492a(23) =509a(24) =523a(25) =553a(26) =575a(27) =645a(28) =719a(29) =797