Both k and its reverse are one more than a square.

Terms

a(0) =1a(1) =2a(2) =5a(3) =10a(4) =50a(5) =101a(6) =626a(7) =730a(8) =1090a(9) =2210a(10) =5477a(11) =7745a(12) =10001a(13) =10610a(14) =71290a(15) =227530a(16) =1000001a(17) =1010026a(18) =1014050a(19) =1040401a(20) =2217122a(21) =2676497a(22) =5053505a(23) =5631130a(24) =6200101a(25) =6265010a(26) =7946762a(27) =100000001a(28) =101808101a(29) =248157010