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A086208 Prime numbers p with the property that the sequence p-1*2, p-2*3, p-3*4, p-4*5, ..., consists only of primes and a final 1. 0

%I

%S 3,7,13,43,73

%N Prime numbers p with the property that the sequence p-1*2, p-2*3, p-3*4, p-4*5, ..., consists only of primes and a final 1.

%C Related to the fact that the list 5, 8, 13, 29, 53, 173, 293 gives the only positive discriminants of class number 1 of the form j^2+1.

%C If we allow the first number that we subtract to be greater than 2, the next sequence after 73, 71, 67, 61,... is 2003, 1831, 1657, 1481, 1303, 1123, 941, 757, 571, 383, 193, 1: start with 2003 and subtract 172,174,176, etc., which is an amusing property of 2003.

%e For example 73 71 67 61 53 43 31 17 1. If the GRH is true this is the last example.

%K nonn,fini,full

%O 0,1

%A Maurice Mischler (maurice.mischler(AT)ima.unil.ch), Aug 27 2003

%E Definition corrected by _Harvey P. Dale_, Jul 25 2015

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Last modified September 26 13:34 EDT 2021. Contains 347668 sequences. (Running on oeis4.)