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 A076565 #17 Apr 28 2021 10:11:12
%S A076565 3,5,7,3,11,13,5,17,19,7,23,5,3,29,31,11,7,37,13,41,43,5,47,7,17,53,
%T A076565 11,19,59,61,7,13,67,23,71,73,5,11,79,3,83,17,29,89,13,31,19,97,11,
%U A076565 101,103,7,107,109,37,113,23,13,17,11,41,5,127,43,131,19,5,137,139,47,13
%N A076565 Greatest prime divisor of 2n+1 (sum of two successive integers).
%H A076565 Robert Israel, <a href="/A076565/b076565.txt">Table of n, a(n) for n = 1..10000</a>
%F A076565 a(n) = A006530(2n+1). - _Robert Israel_, Mar 17 2017
%p A076565 seq(max(numtheory:-factorset(2*n+1)),n=1..200); # _Robert Israel_, Mar 17 2017
%t A076565 Table[FactorInteger[2n + 1][[-1,1]], {n,1, 100}] (* _Indranil Ghosh_, Mar 20 2017 *)
%o A076565 (PARI) for(n=1, 100, print1(vecmax(factor(2*n + 1)[,1]),", ")) \\ _Indranil Ghosh_, Mar 20 2017
%o A076565 (Python)
%o A076565 from sympy.ntheory import primefactors
%o A076565 print([max(primefactors(2*n + 1)) for n in range(1,101)]) # _Indranil Ghosh_, Mar 20 2017
%Y A076565 Cf. A006530.
%K A076565 easy,nonn
%O A076565 1,1
%A A076565 _Zak Seidov_, Oct 19 2002