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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A035092 Smallest k such that (n^2)*k + 1 is prime. 8
1, 1, 2, 1, 4, 1, 4, 3, 2, 1, 6, 3, 4, 1, 8, 1, 12, 4, 30, 1, 2, 3, 24, 1, 18, 1, 2, 4, 12, 2, 16, 12, 2, 3, 6, 1, 4, 13, 6, 1, 10, 2, 12, 6, 2, 6, 4, 8, 6, 9, 6, 9, 28, 1, 4, 1, 10, 3, 6, 4, 46, 4, 4, 3, 4, 1, 4, 3, 22, 6, 10, 2, 4, 1, 2, 7, 22, 3, 6, 4, 6, 3, 10, 1, 4, 3, 2, 4, 6, 1, 10, 4, 2, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Michael De Vlieger, Table of n, a(n) for n = 1..10000

Index entries for sequences related to primes in arithmetic progressions

EXAMPLE

a(40) = 1 because in 1600k + 1 at k = 1, 1601 is the smallest prime;

a(61) = 46 because in the 46*46*k + 1 sequence the first prime appears at k = 46; it is 171167.

MATHEMATICA

Table[k = 1; While[! PrimeQ[k (n^2) + 1], k++]; k, {n, 94}] (* Michael De Vlieger, Dec 17 2016 *)

PROG

(PARI)

a(n)=k=1; while(!isprime(k*n^2+1), k++); k

vector(100, n, a(n)) \\ Derek Orr, Oct 01 2014

CROSSREFS

Analogous case is A034693. See also A005574 and A002496.

Sequence in context: A029205 A229340 A072721 * A160598 A107457 A112350

Adjacent sequences:  A035089 A035090 A035091 * A035093 A035094 A035095

KEYWORD

nonn,easy

AUTHOR

Labos Elemer

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified March 24 04:07 EDT 2017. Contains 283984 sequences.