

A189559


Least prime k such that x' = k has n solutions, where x' is the arithmetic derivative (A003415) of x.


3



2, 5, 31, 167, 151, 491, 983, 887, 311, 1151, 1559, 2111, 1031, 2711, 4391, 4271, 3671, 3191, 5351, 9551, 11471, 14759, 8951, 13751, 11831, 5591, 19991, 10391, 15791, 28031, 30071, 37511, 43151, 27191, 40031, 31391, 52631, 53231, 35591, 52391, 50951
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OFFSET

0,1


COMMENTS

It is much easier finding composite numbers having many solutions. See A189558. For odd numbers, see A189560.


REFERENCES



LINKS



FORMULA

a(n) is the least prime k such that A099302(k) = n.


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



