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 A065853 Let u be any string of 4 digits from {0,...,n-1}; 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). 11
 2, 4, 6, 7, 8, 15, 11, 11, 11, 15, 15, 19, 11, 14, 15, 14, 11, 16, 13, 18, 14, 14, 14, 16, 13, 16, 15, 17, 13, 16, 14, 15, 17, 16, 15, 16, 14, 17, 14, 17, 16, 17, 14, 16, 15, 15, 14, 17, 17, 16, 16, 16, 15, 18, 16, 17, 14, 15, 14, 16, 15, 15, 16, 16, 17, 17, 13, 17, 15, 17, 13 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,1 LINKS EXAMPLE a(2)=2 because 1101 and 1011 are primes and there are no three 4-digit primes with the same number of ones in base 2. MATHEMATICA c[x_, n_] :=   Module[{},    Length[Select[Permutations[x],      First[#] != 0 && PrimeQ[FromDigits[#, n]] &]]]; A065853[n_] := Module[{i},    Return[ Max[Map[c[#, n] &,       DeleteDuplicatesBy[Tuples[Range[0, n - 1], 4],        Table[Count[#, i], {i, 0, n - 1}] &]]]]]; Table[A065853[n], {n, 2, 20}] (* Robert Price, Mar 30 2019 *) CROSSREFS Cf. A065843, A065844, A065845, A065846, A065847, A065848, A065849, A065850, A065851, A065852 Sequence in context: A096750 A088458 A177866 * A048284 A026516 A289012 Adjacent sequences:  A065850 A065851 A065852 * A065854 A065855 A065856 KEYWORD base,nonn AUTHOR Sascha Kurz, Nov 24 2001 EXTENSIONS Definition corrected by David A. Corneth, Apr 23 2016 STATUS approved

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Last modified December 8 01:59 EST 2019. Contains 329850 sequences. (Running on oeis4.)