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

 

Logo

Annual Appeal: Please make a donation to keep the OEIS running. In 2018 we replaced the server with a faster one, added 20000 new sequences, and reached 7000 citations (often saying "discovered thanks to the OEIS").
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A054256 Concatenation of n in base 2 up to base 10 is prime, all numbers are interpreted as decimals. 3
7, 33, 169, 197, 209, 351, 401, 419, 459, 541, 553, 599, 883, 971, 981, 1081, 1107, 1201, 1351, 1363, 2011, 2321, 2347, 2563, 2607, 2679, 2703, 2861, 2869, 2909, 2959, 3033, 3067, 3177, 3333, 3403, 3437, 3461, 3471, 3513, 3601, 3647, 3769, 3821, 3833 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Harvey P. Dale, Table of n, a(n) for n = 0..1000

EXAMPLE

E.g. a(1)=7 -> 111{2}=21{3}=13{4}=12{5}=11{6}=10{7}=7{8}=7{9}=7{10} -> 1112113121110777 is a prime.

MATHEMATICA

Select[Range[4000], PrimeQ[FromDigits[Flatten[Table[IntegerDigits[#, n], {n, 2, 10}]]]]&] (* Harvey P. Dale, Aug 20 2017 *)

CROSSREFS

Cf. A054257, A054258.

Sequence in context: A282991 A295270 A275860 * A085636 A064306 A292427

Adjacent sequences:  A054253 A054254 A054255 * A054257 A054258 A054259

KEYWORD

nonn,base

AUTHOR

Patrick De Geest, Feb 15 2000.

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 December 14 04:53 EST 2018. Contains 318090 sequences. (Running on oeis4.)