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Search: id:A094348
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| A094348 |
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Numbers n such that, for some numbers (j,k), j<=k, n is the smallest positive multiple of j of the first k positive integers. |
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10
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| 1, 2, 4, 6, 12, 24, 36, 48, 60, 72, 120, 180, 240, 360, 420, 720, 840, 1260, 1680, 2520, 5040, 7560, 10080, 15120, 20160, 25200, 27720, 30240, 45360, 50400, 55440, 83160, 110880, 166320, 221760, 277200, 332640, 360360, 498960, 554400, 665280, 720720
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Includes all highly composite numbers (A002182) and least common multiples of 1 through n (A003418). It would be interesting to know: 1) whether or not all deeply composite numbers (A095848, which includes all members of A003418) also belong to this sequence; 2) if 72 is the only member of this sequence not also belonging to A002182 or A095848.
465585120 is the first member of A095848 that is not a member of this sequence. The first members that belong to neither A002182 nor A095848 are 72, 30240, 64864800 and 1470268800. - David Wasserman (dwasserm(AT)earthlink.net), Jun 28 2007
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LINKS
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M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].
M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, Tenth Printing, 1972, p. 844.
J. Britton, Perfect Number Analyzer
Wikipedia, Table of divisors.
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EXAMPLE
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72 is a multiple of seven of the first nine positive integers (namely, 1, 2, 3, 4, 6, 8 and 9). It is the smallest positive integer for which this is true.
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CROSSREFS
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Cf. A096179.
Cf. A003418, A002182, A002201, A072938, A106037, A002110.
Sequence in context: A056795 A141420 A141551 this_sequence A002182 A077006 A004394
Adjacent sequences: A094345 A094346 A094347 this_sequence A094349 A094350 A094351
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KEYWORD
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nonn
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AUTHOR
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Matthew Vandermast (ghodges14(AT)comcast.net), Jun 18 2004, Oct 12 2008
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EXTENSIONS
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More terms from David Wasserman (dwasserm(AT)earthlink.net), Jun 28 2007
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