OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
MAPLE
Res:= NULL:
count:= 0:
for d from 1 while count < 100 do
for m from 3^d to 2*3^d-1 while count < 100 do
L:= convert(m, base, 3)[1..d];
if min(L) <> 0 then next fi;
x:= add((L[i]+7)*10^(i-1), i=1..d);
if isprime(x) then count:= count+1; Res:= Res, x; fi
od od:
Res; # Robert Israel, Jan 07 2020
MATHEMATICA
Select[Prime[Range[8000]], Min[IntegerDigits[ # ]]==7&]
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Zak Seidov, May 07 2005
STATUS
approved