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 A073844 #17 May 26 2022 02:32:45 %S A073844 1,3,41,617,823,643,9721,14593,3803,3803,14405693,10288065751, %T A073844 116216501,12079920647,7552031,435503,1763668414462081,106377431, %U A073844 27961,27961,205126079,84225392753,7347135846537257,437274720469,12792129877,244251294564157 %N A073844 a(1) = 1, a(n) = largest prime divisor of A057137(n). %H A073844 Daniel Suteu, <a href="/A073844/b073844.txt">Table of n, a(n) for n = 1..167</a> %F A073844 a(n) = A006530(A057137(n)). - _Michel Marcus_, May 26 2022 %o A073844 (PARI) a(n) = if(n==1, 1, vecmax(factor(sum(i=1, n, i%10*10^(n-i)))[,1])); \\ _Daniel Suteu_, May 25 2022 %Y A073844 Cf. A006530, A057137. %K A073844 nonn %O A073844 1,2 %A A073844 _Jason Earls_, Sep 02 2002