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A059322 First differences of sequence of consecutive safe primes. 2
2, 4, 12, 24, 12, 24, 24, 60, 12, 48, 36, 84, 12, 24, 84, 12, 24, 60, 24, 132, 120, 24, 24, 96, 36, 168, 96, 24, 12, 48, 72, 48, 36, 96, 204, 84, 120, 12, 24, 36, 108, 240, 12, 120, 240, 60, 24, 60, 36, 24, 96, 48, 36, 264, 156, 156, 24, 60, 84, 60, 72, 48, 12, 120, 24 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..5000

FORMULA

a(n) = A005385(n+1) - A005385(n). - corrected by Harvey P. Dale, Jan 12 2011 and Zak Seidov, Sep 19 2016

EXAMPLE

Except for (5,7) and (7,11), all terms are divisible by 12, since safe primes are congruent to 5 modulo 6 except 7 and safe_prime+6 is not a safe prime. Closest safe primes differ by 12 like (11,23) or (83207,83219).

MATHEMATICA

Differences[Select[Prime[Range[500]], PrimeQ[(#-1)/2]&]]  (* Harvey P. Dale, Jan 12 2011 *)

CROSSREFS

Cf. A005385, A033299.

Sequence in context: A291404 A295954 A052416 * A163908 A230481 A212169

Adjacent sequences:  A059319 A059320 A059321 * A059323 A059324 A059325

KEYWORD

nonn

AUTHOR

Labos Elemer, Jan 26 2001

STATUS

approved

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Last modified June 20 19:36 EDT 2019. Contains 324234 sequences. (Running on oeis4.)