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A181498 Numbers k such that there is at least one pair of twin primes 2^k + 2^j -+ 1 with k/2 <= j <= k. 2
1, 2, 3, 6, 7, 10, 11, 19, 21, 27, 46, 51, 66, 85, 99, 107, 127, 172, 183, 214, 522, 579, 591, 2170, 2538 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(26) > 4000. - Jon E. Schoenfield, Jan 20 2019

LINKS

Table of n, a(n) for n=1..25.

MAPLE

isA181498 := proc(n) local p, k; for k from ceil(n/2) to n do p := 2^n+2^k-1 ; if isprime(p) and isprime(p+2) then return true; end if; end do: false; end proc:

for n from 1 do if isA181498(n) then printf("%d, \n", n) ; end if; end do: # R. J. Mathar, Jan 30 2011

CROSSREFS

Cf. A181408, A181514.

Sequence in context: A204323 A278965 A032858 * A030703 A305927 A271585

Adjacent sequences:  A181495 A181496 A181497 * A181499 A181500 A181501

KEYWORD

nonn,more

AUTHOR

Pierre CAMI, Jan 29 2011

STATUS

approved

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Last modified May 22 00:25 EDT 2019. Contains 323472 sequences. (Running on oeis4.)