login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A064489 Let p = prime(n); a(n) = smallest m such that prime(m) has p digits. 2
5, 26, 1230, 78499, 455052512, 37607912019, 279238341033926, 24739954287740861, 201467286689315906291 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..9.

EXAMPLE

n=5; prime(5)=11 and 11 is the first prime with a prime number of decimal digits.

PROG

(PARI) l(n)=ln=0; while(n, n=floor(n/10); ln++); return(ln); a=0; for(n=1, 10^6, x=l(prime(n)); if(isprime(x), b=x; if(b>a, a=b; print(n))))

CROSSREFS

Cf. A064490.

a(n) = 1 + A006880(A000040(n-1)).

Sequence in context: A226125 A132509 A281747 * A081089 A180928 A118391

Adjacent sequences:  A064486 A064487 A064488 * A064490 A064491 A064492

KEYWORD

base,easy,nonn

AUTHOR

Jason Earls, Oct 04 2001

EXTENSIONS

More terms from David Wasserman, Jul 22 2002

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
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 3 20:04 EDT 2020. Contains 336201 sequences. (Running on oeis4.)