This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A367151 #10 Jan 10 2024 13:26:27 %S A367151 29,67,89,139,223,227,233,239,269,271,277,281,421,457,461,467,499,521, %T A367151 523,571,577,613,617,619,653,659,809,839,881,883,887,1049,1123,1289, %U A367151 1373,1459,1543,1579,1609,1783,2003,2011,2017,2027,2029,2053,2081,2087,2141,2143,2213,2221,2237,2239,2243 %N A367151 Primes whose reversals are triprimes. %H A367151 Robert Israel, <a href="/A367151/b367151.txt">Table of n, a(n) for n = 1..10000</a> %e A367151 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. %p A367151 rev:= proc(n) local L,i; %p A367151 L:= convert(n,base,10); %p A367151 add(L[-i]*10^(i-1),i=1..nops(L)) %p A367151 end proc: %p A367151 select(t -> isprime(t) and numtheory:-bigomega(rev(t)) = 3, [seq(i,i=3..10000,2)]); %t A367151 Select[Prime[Range[350]], PrimeOmega[FromDigits[Reverse[IntegerDigits[#]]]]==3&] (* _Stefano Spezia_, Nov 07 2023 *) %t A367151 Select[Prime[Range[400]],PrimeOmega[IntegerReverse[#]]==3&] (* _Harvey P. Dale_, Jan 10 2024 *) %Y A367151 Cf. A014612, A085778. %K A367151 nonn,base %O A367151 1,1 %A A367151 _Robert Israel_, Nov 06 2023