Deceptive nonprimes: composite numbers k that divide the repunit R_{k-1}.

Terms

a(0) =91a(1) =259a(2) =451a(3) =481a(4) =703a(5) =1729a(6) =2821a(7) =2981a(8) =3367a(9) =4141a(10) =4187a(11) =5461a(12) =6533a(13) =6541a(14) =6601a(15) =7471a(16) =7777a(17) =8149a(18) =8401a(19) =8911a(20) =10001a(21) =11111a(22) =12403a(23) =13981a(24) =14701a(25) =14911a(26) =15211a(27) =15841a(28) =19201a(29) =21931