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Integers k such that A019565(k)-1 and A019565(k)+1 are both primes.
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%I #11 Jan 16 2020 08:43:37

%S 3,7,11,27,31,47,51,67,107,123,135,151,159,163,175,211,251,259,279,

%T 295,479,527,539,607,619,631,771,783,847,999,1035,1051,1071,1183,1279,

%U 1295,1299,1323,1375,1399,1411,1439,1451,1479,1571,1691,1715,1759,1787,1991

%N Integers k such that A019565(k)-1 and A019565(k)+1 are both primes.

%H Amiram Eldar, <a href="/A103798/b103798.txt">Table of n, a(n) for n = 1..10000</a>

%p A019565(3) = 6, 5 and 7 are twin primes, so a(1) = 3.

%p A019565(7) = 30, 29 and 31 are twin primes, so a(2) = 7.

%Y Cf. A019565, A103796, A103797.

%K easy,nonn

%O 1,1

%A _Lei Zhou_, Feb 22 2005