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 A252944 Fermat pseudoprimes that are not Carmichael numbers and have only composite XOR couples as defined in A182108. 0
 23377, 31417, 49981, 74665, 220729, 435671, 679729, 769757, 852481, 915981, 1016801, 1023121, 1128121, 1397419, 2008597, 2987167, 3073357, 4014361 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS There are 433 Fermat pseudoprimes that aren't Carmichael numbers below 2^22, but only 18 have this property. Carmichael numbers that have this property are in A182116. LINKS PROG (MAGMA) function IsClardynum(X, i)   if i eq 1 then     return true;   else     xornum:=2^i - 2;     xorcouple:=BitwiseXor(X, xornum);     if (IsPrime(xorcouple)) then        return false;     else        return IsClardynum(X, i-1);     end if;   end if; end function; for n:= 3 to 1052503 by 2 do   if (IsOne(2^(n-1) mod n)       and not IsPrime(n)       and not n mod CarmichaelLambda(n) eq 1       and IsClardynum(n, Ilog2(n)))       then n;   end if; end for; CROSSREFS Cf. A153508, A001567, A252943, A182108, A182116. Sequence in context: A205834 A184229 A153771 * A246891 A189656 A204074 Adjacent sequences:  A252941 A252942 A252943 * A252945 A252946 A252947 KEYWORD nonn,more AUTHOR Brad Clardy, Dec 25 2014 STATUS approved

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Last modified August 14 18:13 EDT 2022. Contains 356122 sequences. (Running on oeis4.)