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Search: id:A087450
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| A087450 |
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Smallest number (see comment for representation) with all identical digits having n distinct prime divisors. |
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+0
2
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| 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
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Sequence represented by citing the number of repeated digits concatenated with that digit, i.e. a(8) = 122.
No more terms < 3600. - David Wasserman (wasserma(AT)spawar.navy.mil), Jun 03 2005
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EXAMPLE
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a(6) = 86 because 66666666= 2*3*11*73*101*137, is 8 digits long and has 6 distinct prime divisors.
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MATHEMATICA
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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}]
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CROSSREFS
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Cf. A087331.
Adjacent sequences: A087447 A087448 A087449 this_sequence A087451 A087452 A087453
Sequence in context: A072239 A079350 A070605 this_sequence A046465 A134926 A105744
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KEYWORD
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base,nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Sep 06 2003
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EXTENSIONS
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More terms from David Wasserman (wasserma(AT)spawar.navy.mil), Jun 03 2005
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