cp's OEIS Frontend

A224911 Greatest prime dividing A190339(n).

%I A224911 #25 Nov 07 2023 08:14:34
%S A224911 2,3,5,7,7,11,13,13,17,19,19,23,23,23,29,31,31,31,37,37,41,43,43,47,
%T A224911 47,47,53,53,53,59,61,61,61,67,67,71,73,73,73,79,79,83,83,83,89,89,89,
%U A224911 89,97,97,101,103,103,107,109,109,113,113,113,113,113,113,113,127,127,131,131
%N A224911 Greatest prime dividing A190339(n).
%C A224911 It appears that a(n) = A060308(n+1), verified for n <=420. - _R. J. Mathar_, Apr 28 2013
%C A224911 This appears to be a sequence of nondecreasing primes containing each prime at least once.
%C A224911 We might also consider a sequence b(n) defined by 2 followed by A006094(n): 2, 6, 15, 35, 77, 143, 221, ... . A190339(n) is also divisible by a stuttered version of b(n), namely by the sequence 2, 6, 15, 35, 35, 77, 143, 143, ... .
%F A224911 a(n) = A006530(A190339(n)).
%e A224911 a(0) = 6/2 = 3, a(1) = 15/3 = 5, a(2) = 105/15 = 7, a(3) = 105/15 = 7, a(4) = 231/21 = 11.
%p A224911 A224911 := proc(n)
%p A224911     A006530(A190339(n)) ;
%p A224911 end proc: # _R. J. Mathar_, Apr 25 2013
%t A224911 nmax = 67; b[n_] := BernoulliB[n]; b[1] = 1/2; bb = Table[b[n], {n, 0, 2*nmax-1}]; diff = Table[Differences[bb, n], {n, 1, nmax}]; FactorInteger[#][[-1, 1]]& /@ Denominator[Diagonal[diff]] (* _Jean-François Alcover_, Mar 03 2014 *)
%Y A224911 Cf. A006530, A060308, A065091, A190339, A120303, A060265.
%K A224911 nonn
%O A224911 0,1
%A A224911 _Paul Curtz_, Apr 19 2013