login
The OEIS is supported by
the many generous donors to the OEIS Foundation
.
Hints
(Greetings from
The On-Line Encyclopedia of Integer Sequences
!)
A108518
a(n) is the smallest natural number m such that (10^n)! + m is prime.
1
1, 11, 229, 1283
(
list
;
graph
;
refs
;
listen
;
history
;
text
;
internal format
)
OFFSET
0,2
COMMENTS
If a(n) is composite then a(n)>10^(2n)+2*10^n. Conjecture: All terms are noncomposite numbers.
LINKS
Table of n, a(n) for n=0..3.
EXAMPLE
a(3)=1283 because (10^3)!+1283 is prime and for 0<m<1283 1000!+m is
composite.
MATHEMATICA
a[n_] := (For[m = 1, ! PrimeQ[(10^n)! + m], m++ ]; m); Do[Print[a[n]], {n, 0, 3}]
sp[n_]:=Module[{c=(10^n)!}, NextPrime[c]-c]; Array[sp, 4, 0] (*
Harvey P. Dale
, Jul 29 2013 *)
CROSSREFS
Cf.
A108519
.
Sequence in context:
A289716
A305141
A296592
*
A346423
A077736
A068122
Adjacent sequences:
A108515
A108516
A108517
*
A108519
A108520
A108521
KEYWORD
more
,
nonn
AUTHOR
Farideh Firoozbakht
, Jul 10 2005
STATUS
approved
Lookup
|
Welcome
|
Wiki
|
Register
|
Music
|
Plot 2
|
Demos
|
Index
|
Browse
|
More
|
WebCam
Contribute new seq. or comment
|
Format
|
Style Sheet
|
Transforms
|
Superseeker
|
Recents
The OEIS Community
| Maintained by
The OEIS Foundation Inc.
License Agreements, Terms of Use, Privacy Policy.
.
Last modified March 29 09:14 EDT 2024. Contains 371268 sequences. (Running on oeis4.)