

A096841


Numbers n such that sum of divisors of these numbers gives a decimal repdigit.


6



1, 2, 3, 4, 5, 7, 43, 146, 365, 438, 443, 803, 887, 2221, 4442, 6663, 8887, 87876, 88183, 153837, 250244, 285597, 292860, 296294, 302877, 307674, 344268, 351612, 380718, 403398, 423260, 441821, 444443, 550238, 579038, 584438, 588974, 593163, 600363
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OFFSET

1,2


LINKS

Giovanni Resta, Table of n, a(n) for n = 1..365


EXAMPLE

n=43:sigma[43]=44; regular solutions:repdigit1=prime.


MATHEMATICA

rd[x_] := Length[Union[IntegerDigits[x]]] Do[s = rd[DivisorSigma[1, n]]; s1 = DivisorSigma[1, n]; If[Equal[s, 1], Print[{n, s1}]; ta[[u]] = n; u = u + 1], {n, 1, 1000000}]; ta; DivisorSigma[1, ta]
Select[Range[650000], Length[Union[IntegerDigits[DivisorSigma[1, #]]]]==1&] (* Harvey P. Dale, May 11 2019 *)


CROSSREFS

Cf. A096503A096508, A096841A096846, A000203.
Sequence in context: A263043 A028980 A183108 * A029963 A259389 A277217
Adjacent sequences: A096838 A096839 A096840 * A096842 A096843 A096844


KEYWORD

base,nonn


AUTHOR

Labos Elemer, Jul 15 2004


STATUS

approved



