A065849 Let u be any string of n digits from {0,...,7}; let f(u) = number of distinct primes, not beginning with 0, formed by permuting the digits of u to a base-8 number; then a(n) = max_u f(u).

1, 2, 3, 11, 23, 113, 425, 1912, 11872, 57918, 303157, 1757094, 9777949, 59129172

Offset

1,2

Links

Table of n, a(n) for n=1..14.

Example

a(2)=2 because 15 and 51 (written in base 8) are primes (13 and 41).
a(3)=3 because 531, 351 and 513 (in base 8) are primes (107, 233, 331), or 145, 415 and 541 (in base 8) are primes (101, 269, 353), or 147, 417 and 471 are primes (103, 271, 313) etc. - R. J. Mathar, Apr 23 2016

Mathematica

c[x_] := Module[{},
   Length[Select[Permutations[x],
     First[#] != 0 && PrimeQ[FromDigits[#, 8]] &]]];
A065849[n_] := Module[{i},
   Return[Max[Map[c, DeleteDuplicatesBy[Tuples[Range[0, 7], n],
       Table[Count[#, i], {i, 0, 7}] &]]]]];
Table[A065849[n], {n, 1, 7}] (* Robert Price, Mar 30 2019 *)

Crossrefs

Cf. A065843, A065844, A065845, A065846, A065847, A065848, A065850, A065851, A065852, A065853.

Sequence in context: A292112 A363141 A374914 * A136402 A137811 A041955

Adjacent sequences: A065846 A065847 A065848 * A065850 A065851 A065852

Keyword

base,more,nonn

Author

Sascha Kurz, Nov 24 2001

Extensions

2 more terms from Sean A. Irvine, Sep 06 2009

Definition corrected by David A. Corneth, Apr 23 2016

a(13) from Michael S. Branicky, Jul 08 2024

a(14) from Michael S. Branicky, Jul 22 2024

Status

approved