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%I #6 May 26 2017 22:52:32
%S 17,53,71,1039,1429,1559,1949,2339,2729,3119,3769,4159,33857,34883,
%T 40013,41039,48221,50273,54377,58481,61559,63611,69767,70793,74897,
%U 76949,84131,86183,89261,96443,100547,101573,104651,106703,110807,111833,112859,117989,120041
%N Primes that can be generated by the concatenation in base 8, in descending order, of two consecutive integers read in base 10.
%e 1 and 2 in base 8 are 1 and 2 and concat(2,1) = 21 in base 10 is 17;
%e 7 and 8 in base 8 are 7 and 10 and concat(10,7) = 107 in base 10 is 71.
%p with(numtheory): P:= proc(q,h) local a,b,c,d,k,n; a:=convert(q+1,base,h); b:=convert(q,base,h); c:=[op(a),op(b)]; d:=0; for k from nops(c) by -1 to 1 do d:=h*d+c[k]; od; if isprime(d) then d; fi; end: seq(P(i,8),i=0..1000);
%t With[{b = 8}, Select[Map[FromDigits[Flatten@ IntegerDigits[#, b], b] &, Reverse /@ Partition[Range[0, 250], 2, 1]], PrimeQ]] (* _Michael De Vlieger_, May 25 2017 *)
%Y Cf. A000040, A052089.
%K nonn,base,easy
%O 1,1
%A _Paolo P. Lava_, May 24 2017
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