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Search: id:A067128
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| A067128 |
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Ramanujan's largely composite numbers, defined to be n such that d(n) >= d(k) for k = 1 to n-1. |
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+0
5
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| 1, 2, 3, 4, 6, 8, 10, 12, 18, 20, 24, 30, 36, 48, 60, 72, 84, 90, 96, 108, 120, 168, 180, 240, 336, 360, 420, 480, 504, 540, 600, 630, 660, 672, 720, 840, 1080, 1260, 1440, 1680, 2160, 2520, 3360, 3780, 3960, 4200, 4320, 4620, 4680, 5040, 7560, 9240
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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This sequence is contained in A034287; are they identical? They match for n up to 1500000.
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LINKS
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T. D. Noe, Table of n, a(n) for n = 0..193
J. L. Nicolas and G. Robin, Highly Composite Numbers by Srinivasa Ramanujan, The Ramanujan Journal, Vol. 1(2), pp. 119-153, Kluwer Academics Pub.
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EXAMPLE
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8 is a term as d(8) = 4 and d(k) <= 4 for k = 1,...,7.
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MATHEMATICA
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For[n=1; max=0, True, n++, If[(d=DivisorSigma[0, n])>=max, Print[n]; max=d]]
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CROSSREFS
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For n with strictly increasing number of divisors, see A002182.
Adjacent sequences: A067125 A067126 A067127 this_sequence A067129 A067130 A067131
Sequence in context: A020697 A074715 A034287 this_sequence A120432 A020490 A014875
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KEYWORD
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easy,nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Jan 09 2002
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EXTENSIONS
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Edited by Dean Hickerson (dean(AT)math.ucdavis.edu), Jan 15 2002, and by T. D. Noe (noe(AT)sspectra.com), Nov 07 2002
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