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Search: id:A132195
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| A132195 |
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Number of three-prime Carmichael numbers less than 10^n. |
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+0
1
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| 1, 7, 12, 23, 47, 84, 172, 335, 590, 1000, 1858, 3284, 6083, 10816, 19539, 35586, 65309, 120625, 224763, 420658, 790885, 1494738
(list; graph; listen)
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OFFSET
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3,2
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COMMENT
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Chick abstract: "Bounds and other relations involving variables connected with Carmichael numbers are reviewed and extended. Families of numbers or individual numbers attaining or approaching these bounds are given. A new algorithm for finding three-prime Carmichael numbers is described, with its implementation up to 10^{24}. Statistics relevant to the distribution of three-prime Carmichael numbers are given, with particular reference to the conjecture of Granville and Pomerance..."
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REFERENCES
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A. Granville and C. Pomerance, Two contradictory conjectures concerning Carmichael numbers, Math. Comp. 71 (2001), 883-908.
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LINKS
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J. M. Chick, Carmichael number variable relations: three-prime Carmichael numbers up to 10^24, November 19, 2007, Table 1, p. 34.
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FORMULA
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a(n) = C_3(n) in Table 1, p. 34 of Chick = card{c such that c is in A002997 INTERSECTION A014612, and c <= 10^n}.
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CROSSREFS
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Cf. A000040, A002997, A001567, A014612, A064238-A064262, A006931, A055553.
Sequence in context: A071247 A025006 A097925 this_sequence A076852 A011996 A093025
Adjacent sequences: A132192 A132193 A132194 this_sequence A132196 A132197 A132198
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KEYWORD
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nonn
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AUTHOR
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Jonathan Vos Post (jvospost2(AT)yahoo.com), Nov 19 2007
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