OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
MAPLE
Res:= 7:
A:= {7}: B:= {$1..6}:
for d from 2 to 4 do
A:= {seq(seq(10*a+i, i=0..7), a=A), seq(10*b+7, b=B)}:
B:= {seq(seq(10*b+i, i=0..6), b=B)}:
Res:= Res, op(sort(convert(select(isprime, A), list)))
od:
Res; # Robert Israel, Jan 01 2019
MATHEMATICA
Select[Prime[Range[200]], Max[IntegerDigits[ # ]]==7&]
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Zak Seidov, May 07 2005
STATUS
approved