Even squarefree numbers.

Terms

a(0) =2a(1) =6a(2) =10a(3) =14a(4) =22a(5) =26a(6) =30a(7) =34a(8) =38a(9) =42a(10) =46a(11) =58a(12) =62a(13) =66a(14) =70a(15) =74a(16) =78a(17) =82a(18) =86a(19) =94a(20) =102a(21) =106a(22) =110a(23) =114a(24) =118a(25) =122a(26) =130a(27) =134a(28) =138a(29) =142