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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
OFFSET
0,1
COMMENTS
It is much easier finding composite numbers having many solutions. See A189558. For odd numbers, see A189560.
REFERENCES
See A003415.
LINKS
FORMULA
a(n) is the least prime k such that A099302(k) = n.
CROSSREFS
KEYWORD
nonn
AUTHOR
T. D. Noe, Apr 24 2011
STATUS
approved