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 A180555 Primes that become a different prime under the mapping 6 <=> 7. 1
 61, 71, 163, 173, 601, 619, 643, 701, 719, 743, 1609, 1621, 1709, 1721, 1861, 1871, 2689, 2789, 3361, 3371, 3671, 3761, 4261, 4271, 4363, 4373, 4603, 4621, 4651, 4703, 4721, 4751, 4861, 4871, 5563, 5573, 5641, 5669, 5683, 5741, 5779, 5783, 5869, 5879 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Robert Israel, Table of n, a(n) for n = 1..10000 Index to Primes, Primes that become a different prime under some mapping. MAPLE g:= proc(n) local L, i;   L:= subs({6=7, 7=6}, convert(n, base, 10));   add(L[i]*10^(i-1), i=1..nops(L)) end proc: filter:= proc(x) local y;   if not isprime(x) then return false fi;   y:= g(x);   y <> x and isprime(y) end proc: select(filter, [seq(i, i=3..10000, 2)]); # Robert Israel, Nov 12 2019 MATHEMATICA fQ[n_] := Block[{id = IntegerDigits@n}, (MemberQ[id, 6] || MemberQ[id, 7]) && PrimeQ[ FromDigits[ id /. {6 -> 7, 7 -> 6}] ]]; Select[ Prime@ Range@ 780, fQ] CROSSREFS Cf. A171040, A175791, A180517 thru A180559, A175789, A180560, A180561. Sequence in context: A043993 A165287 A064229 * A039478 A109549 A139944 Adjacent sequences:  A180552 A180553 A180554 * A180556 A180557 A180558 KEYWORD base,nonn AUTHOR Zak Seidov and Robert G. Wilson v, Sep 09 2010 STATUS approved

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Last modified November 27 07:28 EST 2021. Contains 349365 sequences. (Running on oeis4.)