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 A077576 #15 May 26 2022 07:04:18 %S A077576 1,23,19,263,823,678901,50993,1279,211,150866941,353594393,757819, %T A077576 9012345678901,213408443,11904282563,435503,21339439879,7403356241, %U A077576 13212859242013,27961,205126079,5201061865265117273,54843374833199,1384232185401581113277,12792129877 %N A077576 a(1) = 1; for n > 1, a(n) = largest prime divisor of A062273(n). %H A077576 Daniel Suteu, <a href="/A077576/b077576.txt">Table of n, a(n) for n = 1..131</a> %F A077576 a(n) = A006530(A062273(n)). - _Michel Marcus_, May 26 2022 %o A077576 (PARI) f(n) = sum(i=1, n, ((n*(n-1)/2+i) % 10)*10^(n-i)); \\ A062273 %o A077576 a(n) = my(x=f(n)); if (x==1, 1, vecmax(factor(x)[,1])); \\ _Michel Marcus_, May 26 2022 %Y A077576 Cf. A006530, A062273. %K A077576 base,nonn %O A077576 1,2 %A A077576 _Amarnath Murthy_, Nov 11 2002 %E A077576 More terms from _Sascha Kurz_, Jan 12 2003 %E A077576 a(24)-a(25) from _Daniel Suteu_, May 25 2022