A095750 "Degree" of the Sophie Germain primes (A005384).

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, 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, 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

Offset: 0

Author

Andrew S. Plewe, Jul 09 2004

Keywords

• easy
• nonn

Comments

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.

This sequence can be obtained by subtracting 2 from A074313 and then deleting all negative members. - David Wasserman, Sep 13 2007

Examples

			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.
		

Links

• C. K. Caldwell, Cunningham Chains.
• Eric Weisstein's World of Mathematics, Cunningham Chain.

Crossrefs

Cf. A005384.

Extensions

More terms from David Wasserman, Sep 13 2007