A181408 Numbers n such that there is at least one pair of twin primes 2^n - 2^k - 1 and 2^n - 2^k + 1 with n/2 <= k < n.
3, 4, 8, 14, 20, 30, 49, 66, 94, 108, 124, 137, 145, 193, 204, 252, 280, 288, 326, 384, 390, 403, 437, 466, 528, 584, 665, 881, 1260, 1538, 1997, 2418, 2460, 2690, 3684, 4006, 5035, 5274, 7748, 8628
Offset: 1
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PARI
isok(n) = {for (k=ceil(n/2), n-1, p = 2^n - 2^k - 1 ; if (isprime(p) && isprime(p+2), return(1)););} \\ Michel Marcus, Dec 23 2015
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