n*10^3-1, n*10^3-3, n*10^3-7 and n*10^3-9 are all prime.

Terms

a(0) =248a(1) =302a(2) =1094a(3) =5462a(4) =6716a(5) =7274a(6) =7478a(7) =9542a(8) =10193a(9) =13217a(10) =16199a(11) =18560a(12) =20714a(13) =22205a(14) =28856a(15) =29843a(16) =31949a(17) =34457a(18) =35387a(19) =36767a(20) =36977a(21) =36983a(22) =40958a(23) =41393a(24) =45167a(25) =45347a(26) =47273a(27) =47468a(28) =47567a(29) =57101