Lucky numbers with size of gaps equal to 4 (upper terms).

Terms

a(0) =7a(1) =13a(2) =25a(3) =37a(4) =67a(5) =73a(6) =79a(7) =115a(8) =133a(9) =163a(10) =193a(11) =205a(12) =223a(13) =235a(14) =241a(15) =289a(16) =307a(17) =331a(18) =361a(19) =433a(20) =487a(21) =541a(22) =583a(23) =619a(24) =643a(25) =655a(26) =727a(27) =739a(28) =745a(29) =781