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 A385721 #25 Aug 16 2025 23:55:59 %S A385721 2,23,2357,2357137939171,2357137939171373,23571379391713739, %T A385721 2357137939171373917139397137,2357137939171373917139397137937179, %U A385721 235713793917137391713939713793717991737391137913793911739171337137177939739397199113939713,2357137939171373917139397137937179917373911379137939117391713371371779397393971991139397137971939131 %N A385721 Primes in A386964. %C A385721 From _Michael S. Branicky_, Aug 12 2025: (Start) %C A385721 Also, numbers b(k) such that b(k) is prime, where b(1) = prime(1) = 2, b(n) = 10*b(n-1) + (prime(n) mod 10), as noted in Comments in A276481. %C A385721 a(n) has A276481(n) digits, so a(14) has 7923 digits. (End) %H A385721 Michael S. Branicky, <a href="/A385721/b385721.txt">Table of n, a(n) for n = 1..13</a> %F A385721 a(n) = A386964(A276481(n)). - _Michael S. Branicky_, Aug 12 2025 %t A385721 a[1]=2; a[n_]:=10a[n-1]+Mod[Prime[n], 10];Select[Array[a,100],PrimeQ] (* _James C. McMahon_, Aug 16 2025 *) %Y A385721 Cf. A007652, A276481, A386964. %K A385721 nonn,base %O A385721 1,1 %A A385721 _Rajsaday Dutt_, Aug 04 2025