A224911 Greatest prime dividing A190339(n).

2, 3, 5, 7, 7, 11, 13, 13, 17, 19, 19, 23, 23, 23, 29, 31, 31, 31, 37, 37, 41, 43, 43, 47, 47, 47, 53, 53, 53, 59, 61, 61, 61, 67, 67, 71, 73, 73, 73, 79, 79, 83, 83, 83, 89, 89, 89, 89, 97, 97, 101, 103, 103, 107, 109, 109, 113, 113, 113, 113, 113, 113, 113, 127, 127, 131, 131

Offset

0,1

Comments

It appears that a(n) = A060308(n+1), verified for n <=420. - R. J. Mathar, Apr 28 2013

This appears to be a sequence of nondecreasing primes containing each prime at least once.

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, ... .

Links

Table of n, a(n) for n=0..66.

Formula

a(n) = A006530(A190339(n)).

Example

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.

Maple

A224911 := proc(n)
    A006530(A190339(n)) ;
end proc: # R. J. Mathar, Apr 25 2013

Mathematica

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 *)

Crossrefs

Cf. A006530, A060308, A065091, A190339, A120303, A060265.

Sequence in context: A039734 A020482 A060308 * A270176 A064142 A067792

Adjacent sequences: A224908 A224909 A224910 * A224912 A224913 A224914

Keyword

nonn

Author

Paul Curtz, Apr 19 2013

Status

approved