a(n) not of form prime +- a(k), k < n.

Terms

a(0) =0a(1) =1a(2) =9a(3) =15a(4) =21a(5) =25a(6) =33a(7) =39a(8) =45a(9) =49a(10) =55a(11) =63a(12) =69a(13) =75a(14) =81a(15) =85a(16) =91a(17) =95a(18) =99a(19) =105a(20) =111a(21) =115a(22) =119a(23) =123a(24) =129a(25) =133a(26) =141a(27) =145a(28) =153a(29) =159