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A287018 Primes that can be generated by the concatenation in base 2, in ascending order, of two consecutive integers read in base 10. 1

%I #12 May 24 2017 09:14:45

%S 11,37,137,239,661,727,859,991,2081,2341,2731,2861,3121,3251,3511,

%T 9547,10321,10837,11353,13159,13417,13933,14449,15739,34439,40093,

%U 43177,43691,45233,46261,60139,61681,63737,135433,138511,139537,144667,146719,151849,154927

%N Primes that can be generated by the concatenation in base 2, in ascending order, of two consecutive integers read in base 10.

%e 2 and 3 in base 2 are 10 and 11 and concat(10,11) = 1011 is 11 in base 10.

%e 4 and 5 in base 2 are 100 and 101 and concat(100,101) = 100101 is 37 in base 10.

%p with(numtheory): P:= proc(q) local a,b,c,n; a:=convert(q+1,binary,decimal); b:=convert(q,binary,decimal); c:=convert(b*10^(ilog10(a)+1)+a,decimal,binary); if isprime(c) then c; fi; end: seq(P(i),i=1..1000);

%t Select[Map[FromDigits[Apply[Join, IntegerDigits[#, 2]], 2] &, Partition[Range@ 320, 2, 1]], PrimeQ] (* _Michael De Vlieger_, May 18 2017 *)

%o (PARI) lista(nn) = {for (n=1, nn, if (isprime(p=fromdigits(Vec(concat(binary(n), binary(n+1))), 2)), print1(p, ", ")));} \\ _Michel Marcus_, May 20 2017

%Y Cf. A000040, A030458, A287019.

%Y Subsequence of primes of A087737.

%K nonn,base,easy

%O 1,1

%A _Paolo P. Lava_, May 18 2017

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Last modified April 24 20:08 EDT 2024. Contains 371963 sequences. (Running on oeis4.)