Numbers k such that k + 1, 2k + 1, 3k + 1, 4k + 1, and 6k + 1 are all prime.

Terms

a(0) =1530a(1) =4260a(2) =25410a(3) =26040a(4) =78540a(5) =111720a(6) =174990a(7) =211050a(8) =214830a(9) =395430a(10) =403260a(11) =409290a(12) =459690a(13) =487830a(14) =512820a(15) =711120a(16) =779790a(17) =910560a(18) =1023750a(19) =1135950a(20) =1280370a(21) =1312350a(22) =1451520a(23) =1464810a(24) =1487070a(25) =1563510a(26) =1623360a(27) =1698060a(28) =1824330a(29) =1933680