

A090517


Least k such that floor[(10^n)/k] is prime.


3



2, 9, 12, 13, 28, 19, 7, 27, 12, 13, 17, 74, 17, 14, 82, 66, 36, 44, 9, 36, 21, 13, 9, 90, 7, 19, 149, 51, 321, 35, 12, 14, 140, 13, 28, 42, 34, 36, 153, 155, 133, 46, 73, 106, 162, 109, 122, 42, 62, 422, 29, 231, 38, 34, 340, 295, 151, 197, 94, 19, 17, 83, 131, 66, 36
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OFFSET

1,1


LINKS



EXAMPLE

a(1) = 2 as 10/2 = 5 is a prime. a(3) = 12 as floor[1000/12] = 83 is prime.


MATHEMATICA

lkp[n_]:=Module[{k=2, c=10^n}, While[!PrimeQ[Floor[c/k]], k++]; k]; Array[ lkp, 70] (* Harvey P. Dale, Jul 09 2018 *)


CROSSREFS



KEYWORD

base,nonn


AUTHOR



EXTENSIONS

Corrected and extended by Mohammed Bouayoun (bouyao(AT)wanadoo.fr), Jan 28 2004


STATUS

approved



