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 A048796 #21 Mar 26 2025 11:29:38
%S A048796 3,131,32397985356295141314159265358979323
%N A048796 Palindromic primes formed from decimal expansion of Pi written backwards then forwards.
%C A048796 The next term 729096599629...1413141...926995690927 has 2971 digits. - _Metin Sariyar_, Jul 07 2020
%H A048796 Chris K. Caldwell and G. L. Honaker, Jr., <a href="https://primes.utm.edu/curios/page.php?number_id=21081">Prime Curios! 729...927 (2971-digits)</a>
%H A048796 Shyam Sunder Gupta, <a href="https://doi.org/10.1007/978-981-97-2465-9_19">Mystery of pi</a>, Exploring the Beauty of Fascinating Numbers, Springer (2025) Ch. 19, 473-497.
%t A048796 l={};Do[a=Floor[Pi*10^n];r=IntegerReverse[a];r2=Floor[r/10];c=FromDigits[Flatten[IntegerDigits/@Join[r2,a]]];
%t A048796 If[PrimeQ[c],AppendTo[l, c]],{n,0,100}];l (* _Metin Sariyar_, Jul 07 2020 *)
%Y A048796 Cf. A000796, A007523, A039954.
%K A048796 base,nonn,bref
%O A048796 1,1
%A A048796 _G. L. Honaker, Jr._