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 A322828 #17 Dec 31 2018 20:24:07 %S A322828 10,21,32,42,53,63,74,84,94,104,115,125,136,146,156,166,177,187,198, %T A322828 208,218,228,239,249,259,269,279,289,2910,3010,3111,3211,3311,3411, %U A322828 3511,3611,3712,3812,3912,4012,4113,4213,4314,4414,4514,4614,4715,4815,4915,5015,5115 %N A322828 a(n) is the concatenation of n and pi(n). %H A322828 Robert Israel, <a href="/A322828/b322828.txt">Table of n, a(n) for n = 1..10000</a> %H A322828 Chris K. Caldwell and G. L. Honaker, Jr., <a href="https://primes.utm.edu/curios/page.php?number_id=18017">Prime Curios! 1027569834</a> %e A322828 a(5) = 53 because if n=5 then pi(5)=3, therefore concatenation gives 53. %p A322828 a:= n-> parse(cat(n, numtheory[pi](n))): %p A322828 seq(a(n), n=1..60); # _Alois P. Heinz_, Dec 28 2018 %o A322828 (PARI) a(n) = eval(concat(Str(n), Str(primepi(n)))); \\ _Michel Marcus_, Dec 29 2018 %Y A322828 Cf. A000027, A000720, A045532. %K A322828 nonn,base %O A322828 1,1 %A A322828 _G. L. Honaker, Jr._, Dec 26 2018