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"Degree" of the Sophie Germain primes (A005384).
0

%I #10 Apr 03 2023 10:36:10

%S 0,0,1,2,3,0,0,0,1,0,0,0,0,1,0,0,0,0,0,0,2,0,0,0,0,0,0,0,0,0,0,3,0,0,

%T 0,0,0,0,1,0,0,0,0,0,0,0,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,1,0,0,0,0,0,

%U 0,0,0,1,0,0,0,0,0,0,1,1,0,1,0,1,0,0,0,0,0,0,0,0,0,1,0,1,1,0,0,1,0,0,0,0,0

%N "Degree" of the Sophie Germain primes (A005384).

%C This sequence is derived from the special case of Cunningham chains of the first kind where every member of the chain is a Sophie Germain prime.

%C This sequence can be obtained by subtracting 2 from A074313 and then deleting all negative members. - _David Wasserman_, Sep 13 2007

%H C. K. Caldwell, <a href="https://t5k.org/glossary/page.php?sort=CunninghamChain">Cunningham Chains</a>.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/CunninghamChain.html">Cunningham Chain</a>.

%e Entries 0, 0, 1, 2, 3 correspond to the Sophie Germain primes 2, 3, 5, 11, 23. 5 is degree 1 because 5 = (2 * 2) + 1 and 2 is also a Sophie Germain prime. Similarly, 11 = (5 * 2) + 1, therefore 11 is degree 2. 23 = (11 * 2) + 1, thus 23 is degree 3 and so on.

%Y Cf. A005384.

%K easy,nonn

%O 0,4

%A _Andrew S. Plewe_, Jul 09 2004

%E More terms from _David Wasserman_, Sep 13 2007