1,1

f[n_, b_] := Block[{k = 10^(n + 1), p = Permutations[ Join[ Table[b, {i, 1, n}], {x}]], c = Complement[Table[j, {j, 0, 9}], {b}], q = {}}, Do[q = Append[q, Replace[p, x -> c[[i]], 2]], {i, 1, 9}]; r = Min[ Select[ FromDigits /@ Flatten[q, 1], PrimeQ[ # ] & ]]; If[r ? Infinity, r, p = Permutations[ Join[ Table[ b, {i, 1, n}], {x, y}]]; q = {}; Do[q = Append[q, Replace[p, {x -> c[[i]], y -> c[[j]]}, 2]], {i, 1, 9}, {j, 1, 9}]; Min[ Select[ FromDigits /@ Flatten[q, 1], PrimeQ[ # ] & ]]]]; Table[ f[n, 7], {n, 1, 18}]

Cf. A065590, A065581, A037066, A034388, A036507-A036536.

Cf. A037053, A037055, A037057, A037059, A037061, A037063, A037065, A037069, A037071.

Sequence in context: A069449 A140031 A066413 this_sequence A065581 A062646 A009503

Adjacent sequences: A037064 A037065 A037066 this_sequence A037068 A037069 A037070

nonn,base

Patrick De Geest (pdg(AT)worldofnumbers.com), Jan 04 1999.

More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Mar 23 2003