OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
a(3) = 89 is a term because 89 is a prime and its reversal 98 = 2*7^2 is the product of 3 primes, counted with multiplicity.
MAPLE
rev:= proc(n) local L, i;
L:= convert(n, base, 10);
add(L[-i]*10^(i-1), i=1..nops(L))
end proc:
select(t -> isprime(t) and numtheory:-bigomega(rev(t)) = 3, [seq(i, i=3..10000, 2)]);
MATHEMATICA
Select[Prime[Range[350]], PrimeOmega[FromDigits[Reverse[IntegerDigits[#]]]]==3&] (* Stefano Spezia, Nov 07 2023 *)
Select[Prime[Range[400]], PrimeOmega[IntegerReverse[#]]==3&] (* Harvey P. Dale, Jan 10 2024 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Robert Israel, Nov 06 2023
STATUS
approved