A074326 - OEIS

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A074326

Numbers n such that difference between (1+2^n)-th and (2^n)-th primes is 2.

1, 6, 8, 9, 17, 23, 27, 39, 48

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..9.

FORMULA

Solutions to A051439(x) - A033844(x) = 2,

EXAMPLE

n=39: 2^39=549755813888, prime(549755813889) = 16149760533343, prime(549755813888) = 16149760533341, difference=2, just twin primes.

MATHEMATICA

s=0; Do[s=Prime[1+2^n]-Prime[2^n]; If[s==2, Print[{n, Prime[2^n]}]], {n, 1, 40}]

diffQ[n_]:=Module[{prn=Prime[2^n]}, NextPrime[prn]-prn==2]; Select[ Range[ 40], diffQ] (* Harvey P. Dale, Aug 21 2014 *)

CROSSREFS

Cf. A029707, A051439, A033844, A073798, A000079.

Sequence in context: A049721 A092115 A083966 * A342649 A254321 A174213

Adjacent sequences: A074323 A074324 A074325 * A074327 A074328 A074329

KEYWORD

more,nonn

AUTHOR

Labos Elemer, Aug 21 2002

EXTENSIONS

a(9) from Chai Wah Wu, Feb 28 2019

STATUS

approved