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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 (list; graph; refs; listen; history; text; internal format)
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
Sequence in context: A266478 A107389 A261750 * A077483 A119242 A068145
KEYWORD
nonn
AUTHOR
T. D. Noe, Apr 24 2011
STATUS
approved

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Last modified March 29 06:57 EDT 2024. Contains 371265 sequences. (Running on oeis4.)