A128193 First differences of values of n for Cullen primes in A005849.

140, 4572, 1082, 816, 11885, 13796, 177, 27187, 31169, 171594, 98856, 120624, 872929, 4973720, 351333

Offset

1,1

Comments

Carlos Rivera's Problem 50 is devoted to this topic. If we pair differences according to magnitude, we first obtain 177-140=37 a prime. This raises the question as to whether there are other such prime values.

Links

Table of n, a(n) for n=1..15.

Carlos Rivera, Problem 50. Is there a Cullen prime Cn with n prime?, The Prime Puzzles and Problems Connection.

Formula

a(n) = A005849(n+1) - A005849(n). - Michel Marcus, Sep 27 2020

Example

a(1)=140 because the first pair of n are 1 and 141. 141 - 1 = 140.

Crossrefs

Cf. A005849, A128194.

Sequence in context: A255775 A199831 A264310 * A061607 A223349 A282613

Adjacent sequences: A128190 A128191 A128192 * A128194 A128195 A128196

Keyword

nonn,more

Author

Enoch Haga, Feb 18 2007

Extensions

Offset 1 from Michel Marcus, Sep 27 2020

a(14)-a(15) added by Florian Baur, Sep 27 2020

Status

approved