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A065851 Let u be any string of n digits from {0,...,9}; let f(u) = number of distinct primes, not beginning with 0, formed by permuting the digits of u; then a(n) = max_u f(u). 10
1, 2, 4, 11, 39, 148, 731, 4333, 26519, 152526 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..10.

EXAMPLE

a(2)=2 because 13 and 31 are primes.

a(3) because {149, 419, 491, 941} or {179, 197, 719, 971} or {379, 397, 739, 937} are primes. - R. J. Mathar, Apr 23 2016

MATHEMATICA

c[x_] := Module[{},

   Length[Select[Permutations[x],

     First[#] != 0 && PrimeQ[FromDigits[#, 10]] &]]];

A065851[n_] := Module[{i},

   Return[Max[Map[c, DeleteDuplicatesBy[Tuples[Range[0, 9], n],

       Table[Count[#, i], {i, 0, 9}] &]]]]];

Table[A065851[n], {n, 1, 6}] (* Robert Price, Mar 30 2019 *)

CROSSREFS

Cf. A065843, A065844, A065845, A065846, A065847, A065848, A065849, A065850, A065852, A065853

Sequence in context: A101898 A193188 A216810 * A173938 A242790 A013044

Adjacent sequences:  A065848 A065849 A065850 * A065852 A065853 A065854

KEYWORD

base,more,nonn

AUTHOR

Sascha Kurz, Nov 24 2001

EXTENSIONS

1 more term from Sean A. Irvine, Sep 06 2009

Definition corrected by David A. Corneth, Apr 23 2016

STATUS

approved

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Last modified January 17 23:37 EST 2020. Contains 330995 sequences. (Running on oeis4.)