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 A118329 #25 Jul 10 2025 19:40:18 %S A118329 9159655941772190150546035149323841107741493742816721 %N A118329 Catalan-primes: primes formed from the concatenation of initial decimal digits of Catalan's constant. %C A118329 Next term has 276 digits and so is too large to include. %H A118329 Amiram Eldar, <a href="/A118329/b118329.txt">Table of n, a(n) for n = 1..2</a> %H A118329 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/NonRecursions.html">Non Recursions</a>. %H A118329 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ConstantPrimes.html">Constant Primes</a>. %H A118329 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/IntegerSequencePrimes.html">Integer Sequence Primes</a>. %H A118329 <a href="/index/O#oneterm">Index entries for one-term sequences</a>. %F A118329 a(n) = floor(A006752 * 10^(A118328(n)-1)). - _Amiram Eldar_, Jul 09 2025 %e A118329 C = 0.915965594177... and the 52-digit number a(1) = 9159655941772190150546035149323841107741493742816721 is prime. %t A118329 Select[Floor[Catalan*10^Range[0, 300]], PrimeQ] (* _Amiram Eldar_, Jul 09 2025 *) %Y A118329 Cf. A006752, A118328. %K A118329 nonn,bref,base %O A118329 1,1 %A A118329 _Eric W. Weisstein_, Apr 25 2006 %E A118329 Edited by _Charles R Greathouse IV_, Apr 27 2010