OFFSET
1,1
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..300
EXAMPLE
The primes that can be obtained by inserting/placing a digit in a(2) = 23 are 223, 233, 239, 263, 283, 293, etc. a(3) = 223 is the smallest.
MAPLE
a:= proc(n) option remember; local s, w, m;
if n=1 then 2
else w:=a(n-1); s:=""||w; m:=length(s);
min(select(x->length(x)=m+1 and isprime(x),
{seq(seq(parse(cat(seq(s[h], h=1..i), j,
seq(s[h], h=i+1..m))), j=0..9), i=0..m)})[])
fi
end:
seq(a(n), n=1..23); # Alois P. Heinz, Nov 07 2014
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Feb 25 2002
EXTENSIONS
Corrected and extended by Robert Gerbicz, Sep 06 2002
STATUS
approved