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

 

Logo

Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A089726 Smallest prime of the form nk+1, k > n. 2
3, 7, 13, 29, 31, 43, 71, 73, 109, 131, 199, 157, 313, 211, 241, 337, 307, 379, 419, 421, 463, 617, 599, 601, 701, 859, 757, 953, 929, 991, 1117, 1153, 1123, 1259, 1471, 1549, 1481, 1483, 1873, 1721, 1723, 1933, 1979, 2069, 2161, 2347, 2351, 2593, 2549, 2551 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

EXAMPLE

a(7)=71 because 7*10+1=71 is prime, whereas 7*8+1=57 and 7*9+1=64 are composite.

MATHEMATICA

f[n_] := Block[{k = n + 1}, While[ !PrimeQ[k*n + 1], k++ ]; k*n + 1]; Array[f, 50] (* Robert G. Wilson v, Dec 17 2009 *)

CROSSREFS

Cf. A089727.

Sequence in context: A146904 A146432 A258349 * A093575 A080166 A116872

Adjacent sequences:  A089723 A089724 A089725 * A089727 A089728 A089729

KEYWORD

nonn,easy

AUTHOR

Amarnath Murthy, Nov 18 2003

EXTENSIONS

More terms from Hugo Pfoertner, Apr 01 2004

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 November 23 21:46 EST 2017. Contains 295141 sequences.