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A208572 Smallest twin prime > 2^n. 4
3, 5, 11, 17, 41, 71, 137, 269, 521, 1031, 2081, 4127, 8219, 16451, 32801, 65537, 131111, 262151, 524351, 1048889, 2097257, 4194581, 8388617, 16777289, 33554501, 67109321, 134217779, 268435577, 536871017, 1073741831, 2147483867, 4294967387 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..500
EXAMPLE
For n=1 the smallest twin prime > 2^n is 3.
MATHEMATICA
stp[n_]:=Module[{t=NextPrime[n]}, While[!PrimeQ[t+2], t=NextPrime[t]]; t]; Table[stp[2^i], {i, 40}] (* Harvey P. Dale, Aug 24 2013 *)
PROG
(PARI) a(n)=my(t=2^n); while(!ispseudoprime(t+2), t=nextprime(t+1)); t \\ Charles R Greathouse IV, Jun 21 2012
CROSSREFS
Cf. A001359, A208574, A173937 (a(n) - 2^n).
Sequence in context: A128550 A096479 A129809 * A040176 A092873 A158641
KEYWORD
nonn
AUTHOR
Washington Bomfim, Feb 28 2012
STATUS
approved

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Last modified March 4 22:06 EST 2024. Contains 370532 sequences. (Running on oeis4.)