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A224911 Greatest prime dividing A190339(n). 4
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 (list; graph; refs; listen; history; text; internal format)
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-Fran├žois Alcover, Mar 03 2014 *)

CROSSREFS

Cf. A006530, A060308, A065091, A190339.

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

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Last modified February 25 08:42 EST 2020. Contains 332221 sequences. (Running on oeis4.)