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!)
A105347 Concatenation of the largest and the smallest n-digit primes (in that order). 0
72, 9711, 997101, 99731009, 9999110007, 999983100003, 99999911000003, 9999998910000019, 999999937100000007, 99999999671000000007, 9999999997710000000019, 999999999989100000000003 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..12.

Chris Caldwell, The First 10,000 Primes.

EXAMPLE

The largest and smallest 1-digit primes are 7 and 2, so the first term is 72.

The largest and smallest 2-digit primes are 97 and 11, so the second term is 9711.

MAPLE

for n from 0 to 30 do for m from 1 to 10^(n+1)-1 do if isprime(10^(n+1) - m) then printf(`%d`, 10^(n+1)-m); break; fi: od: for m from 1 to 10^(n+1)-1 do if isprime(10^n + m) then printf(`%d`, 10^n+m); break; fi: od: printf(`, `): od: # James A. Sellers, May 02 2005

CROSSREFS

Cf. A104206.

Sequence in context: A178635 A271189 A093272 * A093236 A146500 A271190

Adjacent sequences:  A105344 A105345 A105346 * A105348 A105349 A105350

KEYWORD

nonn,base

AUTHOR

Parthasarathy Nambi, Apr 30 2005

EXTENSIONS

More terms from James A. Sellers, May 02 2005

Offset corrected by Michel Marcus, Aug 18 2017

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 February 27 01:52 EST 2020. Contains 332299 sequences. (Running on oeis4.)