A090510 a(n) is the least prime beginning with prime(n) such that the concatenation a(1)a(2)...a(n) is a prime.

2, 3, 509, 79, 1163, 13033, 1721, 19, 233, 29569, 3119, 37057, 410171, 43003, 47111, 5323, 59219, 61291, 670223, 710911, 73331, 795793, 83399, 894709, 975581, 101383, 1033079, 1071937, 109073, 1130257, 1276397, 1313911, 1378673, 1395469, 1491233

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..461

Maple

dcat:= proc(a, b) 10^(1+ilog10(b))*a+b end proc:
S:= 2: R:= 2:
for n from 2 to 35 do
  found:= false;
  for d from 0 while not found do
     cand:= 10^d*ithprime(n)-1;
     do
       cand:= nextprime(cand);
       if cand >= 10^d*(ithprime(n)+1) then break fi;
       Sc:= dcat(S, cand);
       if isprime(Sc) then found:= true; break fi
   od od;
   R:= R, cand;
   S:= Sc;
od:
R; # Robert Israel, Aug 06 2020

Crossrefs

Cf. A090511.

Sequence in context: A128874 A196070 A173342 * A348360 A004887 A240709

Adjacent sequences: A090507 A090508 A090509 * A090511 A090512 A090513

Keyword

base,nonn

Author

Amarnath Murthy, Dec 06 2003

Extensions

More terms from Max Alekseyev, Feb 08 2010

Status

approved