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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
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
Sequence in context: A295954 A364753 A052416 * A163908 A332666 A230481
KEYWORD
nonn
AUTHOR
Labos Elemer, Jan 26 2001
STATUS
approved

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Last modified March 28 20:05 EDT 2024. Contains 371254 sequences. (Running on oeis4.)