Composite numbers k == 1, 9 (mod 10) such that 5^((k-1)/2) == 1 (mod k).

Terms

a(0) =781a(1) =1541a(2) =1729a(3) =5461a(4) =5611a(5) =6601a(6) =7449a(7) =11041a(8) =12801a(9) =13021a(10) =14981a(11) =15751a(12) =15841a(13) =21361a(14) =24211a(15) =25351a(16) =29539a(17) =38081a(18) =40501a(19) =41041a(20) =44801a(21) =47641a(22) =53971a(23) =67921a(24) =75361a(25) =79381a(26) =90241a(27) =100651a(28) =102311a(29) =104721