login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A136582 Sqrt(10)-primes: primes obtained by concatenating the first digits in the decimal expansion of sqrt(10). 6
3, 31, 3162277, 316227766016837933, 316227766016837933199889354443271 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

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

This sequence is the list of prime terms in A017934.

LINKS

Table of n, a(n) for n=1..5.

FORMULA

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

PROG

(MAGMA) // by Jason Kimberley, Aug 2011

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

  f := Isqrt(10^n);

  if IsPrime(f) then

    printf "%o, ", f;

  end if;

end for;

CROSSREFS

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

Sequence in context: A297480 A282973 A005042 * A173649 A210648 A119937

Adjacent sequences:  A136579 A136580 A136581 * A136583 A136584 A136585

KEYWORD

nonn,base

AUTHOR

Lekraj Beedassy, Jan 09 2008

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified June 24 01:22 EDT 2018. Contains 311819 sequences. (Running on oeis4.)