The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A241569 Primes of the form: (concatenation of first n positive integers) + 1. 2
 2, 13, 123457, 123456789101112131415161718192021222324252627282931 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(5) = 123...868788+1 (a 167-digit number). - Jon E. Schoenfield, Apr 26 2014 LINKS Jinyuan Wang, Table of n, a(n) for n = 1..5 EXAMPLE 123457 is in sequence because 123456+1 = 123457 is prime. MATHEMATICA Select[Table[FromDigits[Flatten[IntegerDigits[Range[n]]]] + 1, {n, 1, 1000}], PrimeQ] (* Bruno Berselli, Apr 27 2014 *) PROG (Magma) c:=0; for d in [1..3] do m:=10^d; for n in [m div 10..m-1] do c:=c*m+n; t:=c+1; if IsPrime(t) then t; end if; end for; end for; // Jon E. Schoenfield, Apr 26 2014 (Magma) [t+1: n in [1..1000] | IsPrime(t+1) where t is Seqint(Reverse(&cat[Reverse(Intseq(k)): k in [1..n]]))]; // Bruno Berselli, Apr 27 2014 CROSSREFS Cf. A241570. Sequence in context: A280798 A118912 A027680 * A262299 A135970 A027738 Adjacent sequences: A241566 A241567 A241568 * A241570 A241571 A241572 KEYWORD nonn,base AUTHOR Vincenzo Librandi, Apr 26 2014 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.

Last modified August 3 21:27 EDT 2024. Contains 374905 sequences. (Running on oeis4.)