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a(n) = prime(prime(2*n)) - prime(2*prime(n)).
2

%I #13 Nov 04 2024 01:32:38

%S -2,4,12,24,30,56,52,78,84,82,108,88,126,144,126,162,150,204,210,210,

%T 248,242,234,348,266,268,320,362,380,394,304,396,340,480,378,420,466,

%U 486,476,464,498,578,476,566,592,678,600,456,524,660,714,742,768,756

%N a(n) = prime(prime(2*n)) - prime(2*prime(n)).

%C As difference of two odd primes, all terms are even.

%H M. F. Hasler, <a href="/A230481/b230481.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A217622(n) - A230460(n) = 2*A230482(n).

%o (PARI) a=n->prime(prime(2*n))-prime(2*prime(n))

%Y Cf. A066066, A000040, A006450, A031215, A217622, A230460.

%K sign

%O 1,1

%A _M. F. Hasler_, Oct 20 2013