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 A051663 Primes p such that there is no Carmichael number pqr, p
 2, 11, 197, 1223, 1487, 4007, 4547, 7823, 9833, 9839, 10259, 11483, 11807, 11909, 13259, 13967, 14207, 15629, 15803, 16139, 16889, 18287, 19583, 22367, 23039, 23879, 24359, 25349, 29339, 30707, 32027, 33343, 34883, 36929, 38747 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 REFERENCES Gilberto Garcia-Pulgarin, Numeros de Carmichael producto de tes primos, preprint, 1999. LINKS Charles R Greathouse IV, Table of n, a(n) for n = 1..544 (all terms < 10^6) Index entries for sequences related to Carmichael numbers EXAMPLE 2 is in the sequence since is no Carmichael number of the form 2rq. PROG (PARI) is(p) = { for( A=1, p-1, my(B=ceil((p^2+1)/A), q, r); while(1, r=(B*(p+A-1)-p)/(A*B-p*p); q=(A*r-A+1)/p; if(p>=q, break); if(denominator(q)==1 && denominator(r)==1 && r>q && (q*r)%(p-1)==1 && isprime(q) && isprime(r), return(0)); B++ ) ); 1 }; \\ Charles R Greathouse IV, Feb 23 2013 CROSSREFS Sequence in context: A140314 A226052 A271429 * A348859 A358649 A188203 Adjacent sequences: A051660 A051661 A051662 * A051664 A051665 A051666 KEYWORD nonn AUTHOR Gilberto Garcia-Pulgarin, Dec 11 1999 EXTENSIONS Edited by Jack Brennen, Jul 01 2008 Corrected by Emmanuel Vantieghem, Nov 26 2012 STATUS approved

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Last modified May 29 12:15 EDT 2023. Contains 363042 sequences. (Running on oeis4.)