A087450 - OEIS

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A087450

Smallest number (see comment for representation) with all identical digits having n distinct prime divisors.

11, 12, 16, 26, 46, 61, 62, 121, 122, 182, 241, 242, 322, 301, 302, 422, 642, 646, 722, 1006, 601, 602, 842, 962, 1261, 1262, 1201, 1202, 2042, 1681, 1682, 1922, 1801, 1802, 2102, 2402, 2522, 3302, 3361, 3362, 3001, 3002

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OFFSET

1,1

COMMENTS

Sequence represented by citing the number of repeated digits concatenated with that digit, i.e. a(8) = 122.

No more terms < 3600. - David Wasserman, Jun 03 2005

LINKS

Table of n, a(n) for n=1..42.

EXAMPLE

a(6) = 86 because 66666666= 2*3*11*73*101*137, is 8 digits long and has 6 distinct prime divisors.

MATHEMATICA

PrimeFactors[n_Integer] := Flatten[Table[ #[[1]], {1}] & /@ FactorInteger[n]]; Do[k = 1; While[t = Table[j*(10^k - 1)/9, {j, 1, 9}]; l = Map[Length, Map[PrimeFactors, t]]; Position[l, n] == {}, k++ ]; d = t[[Position[l, n][[1, 1]]]]; Print[10k + Position[l, n][[1, 1]]], {n, 0, 17}]

CROSSREFS

Cf. A087331.

Sequence in context: A072239 A079350 A070605 * A176650 A046465 A134926

Adjacent sequences: A087447 A087448 A087449 * A087451 A087452 A087453

KEYWORD

base,nonn

AUTHOR

Robert G. Wilson v, Sep 06 2003

EXTENSIONS

More terms from David Wasserman, Jun 03 2005

STATUS

approved