Nonprime numbers with all divisors starting and ending with digit 1.

Terms

a(0) =1a(1) =121a(2) =1111a(3) =1331a(4) =1441a(5) =1661a(6) =1991a(7) =10201a(8) =11231a(9) =11341a(10) =11561a(11) =11671a(12) =12001a(13) =12221a(14) =12661a(15) =12881a(16) =12991a(17) =13211a(18) =13231a(19) =13541a(20) =14201a(21) =14311a(22) =14531a(23) =14641a(24) =14971a(25) =15191a(26) =15251a(27) =15851a(28) =15961a(29) =16181