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 A182030 Least odd number k such that 3*k*2^n-1 and 3*k*2^n+1 are twin primes. 1
 1, 1, 3, 5, 27, 1, 3, 19, 15, 5, 33, 55, 123, 15, 115, 39, 127, 1, 23, 149, 27, 11, 393, 81, 255, 125, 27, 129, 15, 115, 227, 195, 125, 89, 247, 71, 143, 1031, 55, 89, 85, 365, 3, 49, 283, 135, 497, 59, 647, 309, 375, 399, 667, 111, 173, 355, 195, 219, 43, 49 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS 54% of a(n) for n=1 to 1755 are < 0.1*n^2. LINKS Pierre CAMI, Table of n, a(n) for n = 1..1755 MATHEMATICA lon[n_]:=Module[{k=1, n2=3*2^n}, While[!PrimeQ[k*n2-1]||!PrimeQ[k*n2+1], k= k+2]; k]; Array[lon, 60] (* Harvey P. Dale, Nov 27 2015 *) CROSSREFS Cf. A210651. Sequence in context: A154143 A101611 A268409 * A282141 A318321 A279510 Adjacent sequences:  A182027 A182028 A182029 * A182031 A182032 A182033 KEYWORD nonn AUTHOR Pierre CAMI, Apr 07 2012 STATUS approved

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Last modified June 20 12:49 EDT 2021. Contains 345164 sequences. (Running on oeis4.)