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A136582 Sqrt(10)-primes: primes obtained by concatenating the first digits in the decimal expansion of sqrt(10). 6

%I

%S 3,31,3162277,316227766016837933,316227766016837933199889354443271

%N Sqrt(10)-primes: primes obtained by concatenating the first digits in the decimal expansion of sqrt(10).

%C n such that floor(sqrt(10^(2*n-1))) is prime (1, 2, 7, 18, 33, ...) are given in A136583.

%C This sequence is the list of prime terms in A017934.

%F a(n) = A017934(2*A136583(n)-1).

%o (MAGMA) // by _Jason Kimberley_, Aug 2011

%o for n in [1..499 by 2] do

%o f := Isqrt(10^n);

%o if IsPrime(f) then

%o printf "%o,", f;

%o end if;

%o end for;

%Y Cf. A010467, A017934, A017934, A131581, A132153, A136583, A175733, A175734.

%K nonn,base

%O 1,1

%A _Lekraj Beedassy_, Jan 09 2008

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Last modified September 19 15:31 EDT 2019. Contains 327199 sequences. (Running on oeis4.)