(n-th 4k+1 prime plus n-th 4k+3 prime)/4.

Terms

a(0) =2a(1) =5a(2) =7a(3) =12a(4) =15a(5) =18a(6) =24a(7) =27a(8) =33a(9) =39a(10) =42a(11) =45a(12) =48a(13) =54a(14) =61a(15) =69a(16) =72a(17) =78a(18) =83a(19) =89a(20) =91a(21) =102a(22) =106a(23) =110a(24) =117a(25) =123a(26) =126a(27) =130a(28) =136a(29) =144