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A002183 Number of divisors of n-th highly composite number.
(Formerly M0546 N0196)
+0
13
1, 2, 3, 4, 6, 8, 9, 10, 12, 16, 18, 20, 24, 30, 32, 36, 40, 48, 60, 64, 72, 80, 84, 90, 96, 100, 108, 120, 128, 144, 160, 168, 180, 192, 200, 216, 224, 240, 256, 288, 320, 336, 360, 384, 400, 432, 448, 480, 504, 512, 576, 600, 640, 672, 720, 768, 800, 864, 896 (list; graph; listen)
OFFSET

1,2

COMMENT

Record values of tau(n).

RECORDS transform of A000005.

All powers of 2 are present through 2^17. No power of 2 above that is present at least through 2^51. - Comment from Robert G. Wilson v, modified by Ray Chandler, Nov 10 2005

No power of 2 above 2^17 is contained in this sequence - see McRae link for proof. - Graeme McRae (g_m(AT)mcraefamily.com), Apr 27 2006

REFERENCES

S. Ramanujan, Collected Papers, Ed. G. H. Hardy et al., Cambridge 1927; Chelsea, NY, 1962, p. 87.

LINKS

T. D. Noe, Table of n, a(n) for n=1..1000

A. Flammenkamp, First 1200 highly composite numbers

Graeme McRae, Highly Composite Numbers

S. Ramanujan, Table of First 103 Highly Composite Numbers

N. J. A. Sloane, Transforms

Eric Weisstein's World of Mathematics, Highly Composite Number

FORMULA

a(n) = A000005(A002182(n)).

Also record values of differences A006218(p)-A006218(p-1). These record values occur for any p=A002182(q) where q>=2. - Philippe LALLOUET (philip.lallouet(AT)wanadoo.fr), Jun 23 2007

MATHEMATICA

(* Julian#39: calculates Highly composite numbers *), (*Dec. 8, 1997 Mathematica 3.0; D. B. Siano*)

CROSSREFS

Cf. A002182, A000005.

Cf. A006218, A002182,A000005

Sequence in context: A085451 A064150 A067023 this_sequence A060306 A117925 A135571

Adjacent sequences: A002180 A002181 A002182 this_sequence A002184 A002185 A002186

KEYWORD

nonn,nice

AUTHOR

njas

EXTENSIONS

More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Jul 24 2002

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Last modified July 25 07:41 EDT 2008. Contains 142293 sequences.


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