login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A226707 Least number k such that 5^(2^i) + k  is prime for i = 0,1,..,n-1. 4
2, 6, 6, 48, 384, 1518, 2037018, 2037018, 44279730804, 424427587626 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..10.

EXAMPLE

a(5) = 384 because k = 384 is the minimal k such that  N = 5^(2^i) + k is prime for i = 0, 1, 2, 3, 4; N = 389, 409, 1009, 391009, 152587891009. But 5^(2^5) + 384 is divisible by 797 and another prime.

CROSSREFS

Cf. A129613, A225560 A226281.

Sequence in context: A155164 A155948 A228955 * A097504 A189144 A130726

Adjacent sequences:  A226704 A226705 A226706 * A226708 A226709 A226710

KEYWORD

nonn,more

AUTHOR

Robin Garcia, Jun 15 2013

EXTENSIONS

a(10) from Giovanni Resta, Jun 16 2013

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 September 21 07:08 EDT 2019. Contains 327253 sequences. (Running on oeis4.)