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 A245063 Primes p such that (p reversed)-1 is not a prime. 1

%I #10 Sep 08 2022 08:46:08

%S 2,5,7,11,13,17,19,29,31,37,43,53,59,61,67,71,73,79,97,101,103,107,

%T 109,113,127,131,137,139,149,151,157,163,167,173,179,181,191,193,197,

%U 199,211,223,227,229,239,241,263,269,271,277,283,293,307,311,313,317,331

%N Primes p such that (p reversed)-1 is not a prime.

%C Complement of A167216.

%H Andrew Howroyd, <a href="/A245063/b245063.txt">Table of n, a(n) for n = 1..1000</a>

%t Select[Prime[Range[3700]], ! PrimeQ[FromDigits[Reverse[IntegerDigits[#]]] - 1] &]

%o (Magma) [p: p in PrimesInInterval(2, 400) |not IsPrime(q-1) where q is Seqint(Reverse(Intseq(p)))];

%o (PARI) ok(n)={isprime(n)&&!isprime(fromdigits(Vecrev(digits(n)))-1)} \\ _Andrew Howroyd_, Feb 27 2018

%Y Cf. A167216.

%K nonn,base

%O 1,1

%A _Vincenzo Librandi_, Jul 11 2014

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Last modified May 28 04:05 EDT 2023. Contains 362992 sequences. (Running on oeis4.)