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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A124204 Numbers k such that 20*k + 1 is prime. 1
2, 3, 5, 9, 12, 14, 20, 21, 23, 26, 27, 30, 32, 33, 35, 38, 41, 44, 47, 51, 53, 59, 60, 65, 66, 68, 69, 74, 80, 81, 86, 87, 90, 93, 95, 104, 107, 108, 111, 114, 117, 119, 122, 126, 131, 137, 140, 143, 150, 152, 153, 156, 159, 161, 165, 168, 173, 177, 179, 185, 188, 191 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..62.

EXAMPLE

If k=95 then 20*k + 1 = 1901 (prime).

PROG

MAGMA) [n: n in [0..6000] | IsPrime(20*n + 1)] // Vincenzo Librandi, Mar 26 2010

(PARI) is(n)=isprime(20*n+1) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

Sequence in context: A097683 A334264 A141403 * A161412 A099420 A184794

Adjacent sequences:  A124201 A124202 A124203 * A124205 A124206 A124207

KEYWORD

nonn,easy

AUTHOR

Parthasarathy Nambi, Dec 07 2006

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 30 05:03 EDT 2020. Contains 337435 sequences. (Running on oeis4.)