A166333 - OEIS

%I #11 Dec 19 2018 22:17:24

%S 1,2,3,1,5,1,7,1,5,1,11,1,13,1,3,1,17,1,19,1,11,1,23,1,13,1,3,1,29,1,

%T 31,1,17,1,3,1,37,1,3,1,41,1,43,1,23,1,47,1,17,1,11,1,53,1,19,1,29,1,

%U 59,1,61,1,3,1,17,1,67,1,5,1,71,1,73,1,3,1,5,1,79,1,41,1,83,1,43,1,3,1,89,1

%N The largest prime that divides A027642(n) (the denominator of the Bernoulli number B_n), or 1 if A027642(n) is 1.

%C The largest member of the extended prime list A008578 which divides the denominator of Bernoulli(n).

%C Essentially A073409 padded with 1's.

%H Antti Karttunen, <a href="/A166333/b166333.txt">Table of n, a(n) for n = 0..16384</a>

%F a(n) = A006530(A027642(n)). - _Antti Karttunen_, Dec 19 2018

%o (PARI)

%o A006530(n) = if(n>1, vecmax(factor(n)[, 1]), 1);

%o A166333(n) = A006530(denominator(bernfrac(n))); \\ _Antti Karttunen_, Dec 19 2018

%Y Cf. A006530, A027642, A073409, A089026, A166120.

%K nonn

%O 0,2

%A _Paul Curtz_, Oct 12 2009

%E Edited and extended by _R. J. Mathar_, Oct 21 2009

%E Name and comment swapped by _Antti Karttunen_, Dec 19 2018