A081812 - OEIS

%I #13 Jan 14 2025 01:55:36

%S 2,3,2,5,3,7,3,3,5,11,3,13,7,5,4,17,3,19,5,7,11,23,3,5,13,3,7,29,5,31,

%T 5,11,17,7,3,37,19,13,5,41,7,43,11,5,23,47,4,7,5,17,13,53,3,11,7,19,

%U 29,59,5,61,31,7,6,13,11,67,17,23,7,71,3,73,37,5,19,11,13,79,5,4,41,83,7,17

%N If n = p_1^e_1 * ... * p_k^e_k, p_1 < ... < p_k primes, then a(n) = Max{ Max(p_i, e_i) }.

%H Alois P. Heinz, <a href="/A081812/b081812.txt">Table of n, a(n) for n = 2..10000</a>

%p a:= n-> max(ifactors(n)[2]):

%p seq(a(n), n=2..85);  # _Alois P. Heinz_, Aug 03 2022

%t a[n_] := Max[Max @@@ FactorInteger[n]];

%t Table[a[n], {n, 2, 85}] (* _Jean-François Alcover_, Jan 13 2025 *)

%o (PARI) a(n)=local(f); if(n<1,0,f=factor(n); vecmax(vector(matsize(f)[1],k,max(f[k,1],f[k,2]))))

%K nonn

%O 2,1

%A _Benoit Cloitre_, Apr 10 2003