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 A083815 Semiprimes whose prime factors are distinct and the reversal of one factor is equal to the other. 7
 403, 1207, 2701, 7663, 35143, 75007, 117907, 127087, 140209, 173809, 197209, 247021, 257821, 342127, 382387, 643063, 692443, 743623, 1226221, 1341331, 1626151, 1698661, 1739161, 2073991, 2138791, 2528611, 2561011, 3321133 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Products of emirp pairs, sorted. - Lekraj Beedassy, Jan 10 2008 LINKS Robert Israel, Table of n, a(n) for n = 1..10000 EXAMPLE a(2)= 1207 = 17 * 71. MAPLE revdigs:= proc(n) local i, L;   L:= convert(n, base, 10);   add(L[-i]*10^(i-1), i=1..nops(L)) end proc: f:= proc(p) local r;   if not isprime(p) then return NULL fi;   r:= revdigs(p);   if r > p and isprime(r) then r*p fi end proc: sort(map(f, [seq(i, i=13..9999, 2)])); # Robert Israel, Dec 26 2018 CROSSREFS Cf. A001358, A006567, A109308. Sequence in context: A097740 A325151 A213605 * A250893 A261857 A165808 Adjacent sequences:  A083812 A083813 A083814 * A083816 A083817 A083818 KEYWORD base,nonn AUTHOR Jason Earls, Jun 17 2003 EXTENSIONS More terms from Ray Chandler, Jul 22 2003 STATUS approved

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Last modified February 26 05:51 EST 2020. Contains 332277 sequences. (Running on oeis4.)