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%I #14 Aug 13 2024 22:54:00
%S 7,10,13,16,19,36,37,40,43,46,58,63,74,85,88,97,98,104,125,132,143,
%T 153,156,164,168,169,175,188,196,203,206,222,224,233,241,269,292,304,
%U 305,308,311,317,331,333,338,344,359,364,367,368,372,382,389,395,397,409
%N Concatenation of 'prevprime(k) and k and nextprime(k)' is a prime.
%H Andrew Howroyd, <a href="/A034810/b034810.txt">Table of n, a(n) for n = 1..10000</a>
%e n=88 --> previous prime is 83, next prime is 89, thus '838889' is a prime.
%t coQ[n_]:=PrimeQ[FromDigits[Flatten[IntegerDigits[{NextPrime[n,-1],n,NextPrime[n]}]]]]; Select[Range[3,409],coQ[#]&] (* _Jayanta Basu_, May 30 2013 *)
%o (PARI) isok(n)=n>2 && isprime(fromdigits(concat([digits(precprime(n-1)), digits(n), digits(nextprime(n+1))]))) \\ _Andrew Howroyd_, Aug 13 2024
%Y Cf. A034808-A034821.
%K nonn,base
%O 1,1
%A _Patrick De Geest_, Oct 15 1998
%E Offset changed by _Andrew Howroyd_, Aug 13 2024
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