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

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A272768 Greatest prime number with prime(n) prime digits. 2
73, 773, 77773, 7777753, 77777777573, 7777777777573, 77777777777775557, 7777777777777777577, 77777777777777777775353, 77777777777777777777777775737, 7777777777777777777777777777333, 7777777777777777777777777777777773553, 77777777777777777777777777777777777777323 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Pierre CAMI, Table of n, a(n) for n = 1..125

MATHEMATICA

a[n_] := Block[{p=7(10^Prime[n]-1)/9-1}, While[{} != Intersection[ IntegerDigits@p, {0, 1, 4, 6, 8, 9}], p = NextPrime[p, -1]]; p]; Array[a, 13] (* Giovanni Resta, May 06 2016 *)

PROG

(PARI) isok(n) = {if (isprime(n), vd = vecsort(digits(n), , 8); for (i=1, #vd, if (!isprime(vd[i]), return (0))); return (1); ); }

a(n) = {gp = 7*(10^prime(n)-1)/9; while (!isok(gp), gp = precprime(gp-2)); gp; } \\ Michel Marcus, May 06 2016

CROSSREFS

Cf. A264917, A272796.

Sequence in context: A137835 A063784 A066101 * A100412 A169830 A197341

Adjacent sequences:  A272765 A272766 A272767 * A272769 A272770 A272771

KEYWORD

nonn,base

AUTHOR

Pierre CAMI, May 06 2016

EXTENSIONS

More terms from Michel Marcus, May 06 2016

a(57) in the b-file corrected by Giovanni Resta, May 06 2016

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 December 1 20:41 EST 2021. Contains 349435 sequences. (Running on oeis4.)