login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A157520 Table T(n,2) read by row with T(n,2)=least j<k, T(n,1)=k such that sum j+k is the least such that 6*p(k)*p(j)^n -1 and +1 are twin primes with p(i)=i-th prime. 0
3, 1, 2, 1, 3, 1, 1, 1, 5, 1, 2, 1, 8, 1, 4, 3, 3, 1, 9, 4, 9, 5, 9, 4, 5, 2, 6, 2, 12, 5, 1, 1, 13, 4, 9, 1, 12, 3, 31, 1, 3, 2, 6, 3, 63, 3, 27, 4, 13, 2, 44, 9, 41, 6, 78, 3, 25, 3, 35, 3, 47, 1, 37, 8, 24, 1, 40, 3, 20, 1, 73, 1, 107, 26, 39, 2, 24, 1, 119, 27, 73, 47, 2, 1, 14, 5, 31, 5, 64, 7 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..90.

EXAMPLE

p(3)=5,p(1)=2, 6*5*2^1-1=59 is prime, so is 61, so T(1,1)=3 T(1,2)=1.

p(2)=3,p(1)=2, 6*3*2^2-1=71 is prime, so is 73, so T(2,1)=2 T(2,2)=1.

p(3)=5,p(1)=2, 6*5*2^3-1=239 is prime, so is 241, so T(3,1)=3 T(3,2)=1.

CROSSREFS

Sequence in context: A324081 A256262 A332929 * A325116 A227339 A030777

Adjacent sequences:  A157517 A157518 A157519 * A157521 A157522 A157523

KEYWORD

nonn,tabf

AUTHOR

Pierre CAMI, Mar 02 2009

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 30 09:54 EST 2021. Contains 349419 sequences. (Running on oeis4.)