A367151 Primes whose reversals are triprimes.

29, 67, 89, 139, 223, 227, 233, 239, 269, 271, 277, 281, 421, 457, 461, 467, 499, 521, 523, 571, 577, 613, 617, 619, 653, 659, 809, 839, 881, 883, 887, 1049, 1123, 1289, 1373, 1459, 1543, 1579, 1609, 1783, 2003, 2011, 2017, 2027, 2029, 2053, 2081, 2087, 2141, 2143, 2213, 2221, 2237, 2239, 2243

Offset: 1

Author

Robert Israel, Nov 06 2023

Keywords

• nonn
• base

Examples

			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.
		

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A014612, A085778.

Programs

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 *)