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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).
11
1, 2, 3, 11, 23, 113, 425, 1912, 11872, 57918, 303157, 1757094, 9777949, 59129172
OFFSET
1,2
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 *)
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