A059787 - OEIS

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A059787

Distance between 2*(n-th prime) and next prime.

1, 1, 1, 3, 1, 3, 3, 3, 1, 1, 5, 5, 1, 3, 3, 1, 9, 5, 3, 7, 3, 5, 1, 1, 3, 9, 5, 9, 5, 1, 3, 1, 3, 3, 9, 5, 3, 5, 3, 1, 1, 5, 1, 3, 3, 3, 9, 3, 3, 3, 1, 1, 5, 1, 7, 15, 3, 5, 3, 1, 3, 1, 3, 9, 5, 7, 11, 3, 7, 3, 3, 1, 5, 5, 3, 3, 9, 3, 7, 3, 1, 11, 1, 11, 3, 1, 9, 5, 7, 3, 3, 9, 3, 1, 11, 3, 1, 7, 3, 5, 3, 3

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,4

COMMENTS

If a(n)=1 then prime(n) is a Sophie Germain prime.

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

MAPLE

with(numtheory): [seq(nextprime(2*ithprime(k))-2*ithprime(k), k=1..256)];

MATHEMATICA

Table[n2=2Prime[n]; NextPrime[n2]-n2, {n, 110}] (* Harvey P. Dale, Jun 07 2012 *)

PROG