A095750 - OEIS

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

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

OFFSET

0,4

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

LINKS

Table of n, a(n) for n=0..104.

C. K. Caldwell, Cunningham Chains.

Eric Weisstein's World of Mathematics, Cunningham Chain.

EXAMPLE

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.

CROSSREFS

Cf. A005384.

Sequence in context: A292247 A194016 A292256 * A056966 A362363 A037846

Adjacent sequences: A095747 A095748 A095749 * A095751 A095752 A095753

KEYWORD

easy,nonn

AUTHOR

Andrew S. Plewe, Jul 09 2004

EXTENSIONS

More terms from David Wasserman, Sep 13 2007

STATUS

approved