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 A052369 #23 Jul 02 2025 16:01:58 %S A052369 2,3,2,3,5,3,7,5,2,3,5,7,11,3,5,13,3,7,5,2,11,17,7,3,19,13,5,7,11,5, %T A052369 23,3,7,5,17,13,3,11,7,19,29,5,31,7,2,13,11,17,23,7,3,37,5,19,11,13,5, %U A052369 3,41,7,17,43,29,11,5,13,23,31,47,19,3,7,11,5,17,13,7,53,3,11,37,7,19,23 %N A052369 Largest prime factor of n, where n runs through composite numbers. %H A052369 Robert Israel, <a href="/A052369/b052369.txt">Table of n, a(n) for n = 1..10000</a> %F A052369 a(n) = A006530(A002808(n)). [_Reinhard Zumkeller_, Aug 25 2008] %e A052369 First composite is 4, largest prime factor is 2, so a(1)=2. %p A052369 map(t -> max(numtheory:-factorset(t)), remove(isprime,[$2..10^3])); # _Robert Israel_, Aug 10 2014 %t A052369 FactorInteger[#][[-1,1]]&/@Select[Range[150],CompositeQ] (* _Harvey P. Dale_, Jan 24 2016 *) %o A052369 (Magma) [ D[ #D]: n in [2..115] | not IsPrime(n) where D is PrimeDivisors(n) ]; // [_Klaus Brockhaus_, Jun 23 2009] %o A052369 (PARI) forcomposite(n=1, 1e2, p=factor(n)[omega(n), 1]; print1(p, ", ")) \\ _Felix Fröhlich_, Aug 08 2014 %Y A052369 Cf. A002808, A006530, A056608. [From _Reinhard Zumkeller_, Aug 25 2008] %K A052369 nonn,easy %O A052369 1,1 %A A052369 Michael Contente (mec1000(AT)aol.com), Mar 08 2000 %E A052369 More terms from _James Sellers_, Mar 09 2000