A220270 Number of biased numbers (A101550) less than 10^n.

2, 43, 537, 5866, 61466, 630509, 6410996, 64836667, 653704646, 6578501544, 66115091613, 663868597795, 6661437722643, 66808391053328, 669760217536267, 6712237657325964, 67251395887426191

Offset

1,1

Links

Table of n, a(n) for n=1..17.

G. Everest, S. Stevens, D. Tamsett and T. Ward, Primes Generated by Recurrence Sequences, arXiv:math/0412079 [math.NT], 2004-2006.

Formula

a(n) ~ 10^n*log(2) as n -> infinity.

Mathematica

Accumulate@Table[Length@Select[Range[10^(n - 1), 10^n - 1], FactorInteger[#][[-1, 1]] > 2*Sqrt[#] &], {n, 5}] (* or *)
lst = {}; s = -2; Do[Do[If[PrimeQ[i] || FactorInteger[i][[-1, 1]] > 2*Sqrt[i], s++], {i, 10^(n - 1), 10^n - 1}]; AppendTo[lst, s], {n, 5}]; lst

Crossrefs

Cf. A101550, A002162.

Sequence in context: A349927 A112097 A354304 * A240550 A142199 A109948

Adjacent sequences: A220267 A220268 A220269 * A220271 A220272 A220273

Keyword

more,nonn

Author

Arkadiusz Wesolowski, Dec 11 2012

Extensions

a(9)-a(11) from Donovan Johnson, Dec 12 2012

a(12)-a(17) from Hiroaki Yamanouchi, Aug 31 2014

Status

approved