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A234540 Nonprimes n such that n divides sum of the nonprimes up to n. 0
1, 22, 25, 118, 414, 2745, 10623, 63201, 1039161, 1693864, 2285297, 52962021, 66998865, 232974402, 315796805, 336125877, 834972771, 1233903294, 1309750075, 1617454215, 2056836133, 5455816485, 8589896196, 9030058217, 10622144467, 12324258770, 33725308558 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Standard heuristics suggest that this sequence is infinite. - Charles R Greathouse IV, Dec 29 2013

LINKS

Table of n, a(n) for n=1..27.

EXAMPLE

a(2) = 22 because 1 + 4 + 6 + 8 + 9 + 10 + ... + 22 = 176 and 176/22 = 8.

MATHEMATICA

s = 0; Do[If[PrimeQ[k], Continue[]]; s += k; If[Mod[s, k] == 0, Print[k]], {k, 10^10}] (* Gomez *)

Select[Range[10^4], Not[PrimeQ[#]] && Divisible[Sum[Boole[Not[PrimeQ[m]]]m, {m, #}], #] &] (* Alonso del Arte, Dec 29 2013 *)

PROG

(PARI) v=List([s=1]); forcomposite(n=4, 1e9, if(s%n==0, listput(v, n)); s+=n); Vec(v) \\ Charles R Greathouse IV, Dec 29 2013

CROSSREFS

Cf. A007506.

Sequence in context: A045096 A227408 A303304 * A124177 A260990 A260991

Adjacent sequences:  A234537 A234538 A234539 * A234541 A234542 A234543

KEYWORD

nonn

AUTHOR

Vicente Izquierdo Gomez, Dec 27 2013

EXTENSIONS

a(14)-a(27) from Donovan Johnson, Dec 30 2013

STATUS

approved

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Last modified June 25 08:20 EDT 2019. Contains 324347 sequences. (Running on oeis4.)