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A303640 a(n) is the least k > n such that A007504(n) divides A007504(k). 1
3, 3, 9, 13, 33, 15, 121, 84, 103, 26, 259, 295, 433, 71, 111, 331, 317, 366, 649, 80, 283, 274, 429, 4542, 3071, 2138, 4241, 74, 761, 3083, 103, 1847, 1683, 3886, 1233, 470, 2359, 1182, 1797, 3431, 2037, 1767, 7543, 9106, 1867, 656, 5469, 6012, 12245, 2225 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Credit is given for Zak Seidov for doing the calculations.

LINKS

Seiichi Manyama, Table of n, a(n) for n = 1..500

EXAMPLE

A007504(6)=41 and 41|328=A007504(15).

MAPLE

N:= 10^5: # to get all terms before the first term > N

A007504:= ListTools:-PartialSums([seq(ithprime(i), i=1..N)]):

found:= true:

for n from 1 while found do

  found:= false;

  for k from n+1 to N do

    if A007504[k] mod A007504[n] = 0 then

      found:= true;

      A[n]:= k;

      break

    fi

  od

od:

seq(A[i], i=1..n-2); # Robert Israel, May 02 2018

MATHEMATICA

a[n_] := For[tpn = Prime[Range[n]] // Total; tpk = 0; k = n+1, True, k++, tpk += Prime[k]; If[Divisible[tpk, tpn], Return[k]]]; Array[a, 50] (* Jean-Fran├žois Alcover, Mar 22 2019 *)

CROSSREFS

Cf. A000040, A007504.

Sequence in context: A083336 A225436 A183811 * A091328 A138383 A052436

Adjacent sequences:  A303637 A303638 A303639 * A303641 A303642 A303643

KEYWORD

nonn

AUTHOR

J. M. Bergot, Apr 27 2018

EXTENSIONS

More terms from Alois P. Heinz, Apr 27 2018

STATUS

approved

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Last modified July 23 03:00 EDT 2019. Contains 325230 sequences. (Running on oeis4.)