0,1

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.

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.

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

Sequence in context: A051842 A147447 A062605 this_sequence A090968 A020641 A062736

Adjacent sequences: A086205 A086206 A086207 this_sequence A086209 A086210 A086211

nonn,fini,full

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