OFFSET
1,1
COMMENTS
Primes p such that there is no prime whose decimal digits are (in some order) the 9's complements of the decimal digits of p.
Leading zeros are not allowed.
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
a(4)=13 is a member because the 9's complements of the digits 1,3 are 8,2, and none of the integers 28 or 82 is prime.
a(26)=149 is a member because the 9's complements of its digits are 8,5,0, and none of the integers with those digits is prime.
MAPLE
R:= 3, 5:
for d from 2 to 4 do
P:= select(isprime, [seq(i, i=10^(d-1)+1..10^d-1, 2)]);
nP:= nops(P);
Pd:= map(sort@convert, P, base, 10);
Ps:= convert(map(t -> ListTools:-Reverse([9$d]-t), Pd), set);
S:= remove(t -> member(Pd[t], Ps), [$1..nP]);
R:= R, op(P[S]);
od:
R; # Robert Israel, Oct 06 2020
CROSSREFS
KEYWORD
AUTHOR
Robert Israel, Oct 06 2020
STATUS
approved