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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

%I

%S 1,2,4,11,39,148,731,4333,26519,152526

%N 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).

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

%e 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

%t c[x_] := Module[{},

%t Length[Select[Permutations[x],

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

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

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

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

%t Table[A065851[n], {n, 1, 6}] (* _Robert Price_, Mar 30 2019 *)

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

%K base,more,nonn

%O 1,2

%A _Sascha Kurz_, Nov 24 2001

%E 1 more term from _Sean A. Irvine_, Sep 06 2009

%E Definition corrected by _David A. Corneth_, Apr 23 2016

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Last modified February 18 02:57 EST 2020. Contains 332006 sequences. (Running on oeis4.)