A076055 - OEIS

%I #20 Nov 21 2021 07:36:32

%S 14,16,20,30,32,34,35,38,50,70,74,76,91,92,95,98,104,106,110,112,118,

%T 119,124,125,128,130,133,134,136,140,142,145,146,152,160,164,166,170,

%U 172,175,182,188,194,196,200,300,301,305,310,316,320,322,325,328,332

%N Composite numbers which when read backwards are primes.

%C If m is a term, then 10*m is another term. - _Bernard Schott_, Nov 20 2021

%H Michael S. Branicky, <a href="/A076055/b076055.txt">Table of n, a(n) for n = 1..10000</a>

%t Rev[n_]:=FromDigits[Reverse[IntegerDigits[n]]];Select[Range[332],!PrimeQ[#] && PrimeQ[Rev[#]]&] (* _Jayanta Basu_, May 01 2013 *)

%o (Python)

%o from sympy import isprime

%o def ok(n): return not isprime(n) and isprime(int(str(n)[::-1]))

%o print([k for k in range(333) if ok(k)]) # _Michael S. Branicky_, Nov 20 2021

%Y Cf. A076056.

%Y Intersection of A002808 and A095179.

%K base,nonn

%O 1,1

%A _Amarnath Murthy_, Oct 04 2002

%E Corrected and extended by _Sascha Kurz_, Jan 20 2003