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Numbers k such that A025487(k)-1 and A025487(k)+1 are twin primes.
2

%I #8 Aug 05 2024 08:45:07

%S 3,4,6,9,13,15,20,21,24,29,30,42,54,56,59,72,77,83,96,104,105,109,138,

%T 161,166,174,186,203,208,221,232,237,266,270,288,295,336,338,347,387,

%U 389,395,400,401,449,468,469,472,479,506,520,543,584,617,633,643,668

%N Numbers k such that A025487(k)-1 and A025487(k)+1 are twin primes.

%H Amiram Eldar, <a href="/A375198/b375198.txt">Table of n, a(n) for n = 1..10000</a>

%F A025487(a(n)) = A375197(n).

%t Position[Cases[Import["https://oeis.org/A025487/b025487.txt", "Table"], {_, _}][[;; , 2]], _?(PrimeQ[# - 1] && PrimeQ[# + 1] &)] // Flatten

%Y Cf. A001097, A001359, A006512, A014574, A025487, A375197.

%Y Similar sequences: A321995, A353302.

%K nonn

%O 1,1

%A _Amiram Eldar_, Aug 04 2024