OFFSET
1,1
COMMENTS
At least up to n = 10^5, one inserted digit per position suffices. - Robert Israel, Feb 12 2016
LINKS
Matthew M. Conroy and Robert Israel, Table of n, a(n) for n = 1..10000 (n = 1..168 from Matthew M. Conroy)
MAPLE
f:= proc(n) local p, Lp, q0, x, Lx, k, i, q;
# This function attempts to insert one digit in each position.
p:= ithprime(n);
if p < 10 then return p fi;
Lp:= convert(p, base, 10);
k:= nops(Lp);
q0:= add(100^(i-1)*Lp[i], i=1..k);
for x from 0 to 10^k-1 do
Lx:= convert(10^k+x, base, 10);
q:= q0 + 10*add(100^(i-1)*Lx[i], i=1..k-1);
if isprime(q) then return q fi
od:
error("Need more than one digit");
end proc:
map(f, [$1..100]); # Robert Israel, Feb 12 2016
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Feb 21 2003
EXTENSIONS
More terms from Matthew Conroy, Sep 18 2007
STATUS
approved