a(n) = (2^n concatenated with Reverse(2^n)) divided by 11.

Terms

a(0) =1a(1) =2a(2) =4a(3) =8a(4) =151a(5) =293a(6) =586a(7) =11711a(8) =23332a(9) =46565a(10) =931291a(11) =1862582a(12) =3724264a(13) =7447538a(14) =148949851a(15) =297898793a(16) =595787596a(17) =11915660921a(18) =23831312842a(19) =47662625675a(20) =953251523491