A132195 Number of three-prime Carmichael numbers less than 10^n.

1, 7, 12, 23, 47, 84, 172, 335, 590, 1000, 1858, 3284, 6083, 10816, 19539, 35586, 65309, 120625, 224763, 420658, 790885, 1494738

Offset

3,2

Comments

a(n) = C_3(n) in Table 1, p. 34 of Chick (2007-2008) = card{c such that c is in A002997 INTERSECTION A014612 and c <= 10^n}.

Links

Table of n, a(n) for n=3..24.

J. M. Chick, Carmichael number variable relations: three-prime Carmichael numbers up to 10^24, arXiv:0711.2915 [math.NT], 2007-2008, Table 1, p. 34.

Andrew Granville and Carl Pomerance, Two contradictory conjectures concerning Carmichael numbers, Mathematics of Computation, Vol. 71, No. 238 (2002), pp. 883-908.

Crossrefs

For k-prime Carmichael numbers up to 10^n for k = 3,4,...,11, see A132195, A174612, A174613, A174614, A174615, A174616, A174617, A299710, A299711.

Cf. A002997, A006931, A055553.

Sequence in context: A252652 A192752 A097925 * A076852 A011996 A357509

Adjacent sequences: A132192 A132193 A132194 * A132196 A132197 A132198

Keyword

nonn,more

Author

Jonathan Vos Post, Nov 19 2007

Status

approved