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Search: id:A025487
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| A025487 |
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List giving least integer of each prime signature; also products of primorial numbers A002110. |
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+0
182
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| 1, 2, 4, 6, 8, 12, 16, 24, 30, 32, 36, 48, 60, 64, 72, 96, 120, 128, 144, 180, 192, 210, 216, 240, 256, 288, 360, 384, 420, 432, 480, 512, 576, 720, 768, 840, 864, 900, 960, 1024, 1080, 1152, 1260, 1296, 1440, 1536, 1680, 1728, 1800, 1920, 2048, 2160, 2304, 2310
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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All numbers of the form 2^k1*3^k2*...*p_n^k_n, where k1 >= k2 >= ... >= k_n, sorted.
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REFERENCES
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The exponents k1, k2, ... can be read off Abramowitz and Stegun, Handbook, p. 831, column labeled "pi".
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LINKS
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Franklin T. Adams-Watters, Table of n, a(n) for n = 1..10001
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].
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EXAMPLE
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The first few terms are 1, 2, 2^2, 2*3, 2^3, 2^2*3, 2^4, 2^3*3, 2*3*5, ...
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MATHEMATICA
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PrimeExponents[n_] := Flatten[ Table[ # [[2]], {1}] & /@ FactorInteger[n]]; lpe = {}; ln = {1}; Do[pe = Sort@PrimeExponents@n; If[ FreeQ[lpe, pe], AppendTo[lpe, pe]; AppendTo[ln, n]], {n, 2350}]; ln (from Robert G. Wilson v Aug 14 2004)
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CROSSREFS
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Cf. A036035, A025488, A051282. Equals range of values taken by A046523.
Cf. A055932, A036041, A061394, A124832.
Sequence in context: A048951 A058629 A095810 this_sequence A070175 A096850 A062847
Adjacent sequences: A025484 A025485 A025486 this_sequence A025488 A025489 A025490
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KEYWORD
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nonn,easy,nice
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AUTHOR
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David W. Wilson (davidwwilson(AT)comcast.net)
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EXTENSIONS
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Offset corrected by Matt Vandermast, Oct 19 2008
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