A272768 Greatest prime number with prime(n) prime digits.

73, 773, 77773, 7777753, 77777777573, 7777777777573, 77777777777775557, 7777777777777777577, 77777777777777777775353, 77777777777777777777777775737, 7777777777777777777777777777333, 7777777777777777777777777777777773553, 77777777777777777777777777777777777777323

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