This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A249166 #4 Sep 08 2022 08:46:10 %S A249166 11,33,55,77,99,1111,1313,1515,1717,1919,2121,2323,2525,2727,2929, %T A249166 3131,3333,3535,3737,3939,4141,4343,4545,4747,4949,5151,5353,5555, %U A249166 5757,5959,6161,6363,6565,6767,6969,7171,7373,7575,7777,7979,8181,8383,8585,8787 %N A249166 Odd integers concatenated with themselves. %C A249166 Bisection (every other term) of A020338. See A248422 for the complement. %o A249166 (PARI) a(n) = eval(Str(2*n-1,2*n-1)) %o A249166 (Magma) [Seqint(Intseq(n) cat Intseq(n)): n in [1..99 by 2]] %Y A249166 Cf. A020338, A248422. %K A249166 nonn,base %O A249166 1,1 %A A249166 _M. F. Hasler_, Oct 22 2014