OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
MAPLE
extend:= proc(n) local d, x;
d:= n mod 10;
seq(10*n+x, x = select(t -> t >= 0 and t <= 9, [d-7, d-6, d+6, d+7]))
end proc:
R:= 2, 3, 5, 7: count:= 4:
T:= [$1..9]:
for d from 2 while count < 100 do
T:= map(extend, T);
V:= select(isprime, T);
count:= count+nops(V);
R:= R, op(V);
od:
R; # Robert Israel, Oct 17 2023
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, Apr 15 1999
STATUS
approved