

A229272


Numbers n for which n' + n and n'  n are both prime, n' being the arithmetic derivative of n.


4



210, 330, 390, 690, 798, 966, 1110, 1230, 2190, 2310, 2730, 3270, 4110, 4530, 4890, 5430, 6090, 6270, 6810, 6990, 7230, 7890, 8310, 8490, 9030, 9210, 9282, 10470, 10590, 10770, 12090, 12210, 12270, 12570, 12810, 12930, 13110, 13830, 14070, 17070, 17094, 17310
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OFFSET

1,1


COMMENTS

Intersection of A165561 and A229270.


LINKS

Paolo P. Lava, Table of n, a(n) for n = 1..300


MAPLE

with(numtheory); P:=proc(q) local a, n, p; for n from 1 to q do
a:=n*add(op(2, p)/op(1, p), p=ifactors(n)[2]);
if isprime(a+n) and isprime(an) then print(n); fi;
od; end: P(10^5);


PROG

(Python)
from sympy import isprime, factorint
A229272 = []
for n in range(1, 10**5):
....np = sum([int(n*e/p) for p, e in factorint(n).items()]) if n > 1 else 0
....if isprime(np+n) and isprime(npn):
........A229272.append(n)
# Chai Wah Wu, Aug 21 2014


CROSSREFS

Cf. A003415, A165561, A165562, A229269A229271.
Sequence in context: A074159 A033993 A046386 * A046402 A258359 A325991
Adjacent sequences: A229269 A229270 A229271 * A229273 A229274 A229275


KEYWORD

nonn


AUTHOR

Paolo P. Lava, Sep 18 2013


STATUS

approved



