OFFSET
1,1
LINKS
Daniel Suteu, Table of n, a(n) for n = 1..69
FORMULA
EXAMPLE
For n=5: concatenation of {2,3,5,7,11} is 235711 = 7*151*223, largest prime divisor is a(5)=223.
MATHEMATICA
<<NumberTheory`NumberTheoryFunctions` sz[x_] :=FromDigits[Flatten[Table[IntegerDigits[Prime[j]], {j, 1, x}], 1]] Table[Max[PrimeFactorList[sz[w]]], {w, 1, 25}] (* Labos Elemer, Mar 18 2005 *)
Table[FactorInteger[FromDigits[Flatten[IntegerDigits/@Prime[ Range[n]]]]][[-1, 1]], {n, 25}] (* Harvey P. Dale, Apr 27 2015 *)
PROG
(PARI) a(n) = vecmax(factor(eval(concat(apply(s->Str(s), primes(n)))))[, 1]); \\ Daniel Suteu, May 26 2022
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Jason Earls, Sep 08 2002
EXTENSIONS
More terms from Labos Elemer, Mar 18 2005
Edited by Charles R Greathouse IV, Apr 23 2010
STATUS
approved