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%I #4 Feb 27 2009 03:00:00
%S 0,2,6,12,7,4,3
%N Pronic residues. These are analogous to quadratic residues, but use the set of pronics 0 2 6 12 20 30... instead of the quadratics (squares) 0 1 4 9 16 25... The example shown above is mod 13.
%C It is noted that when the modulus is not prime that a 0 may appear in the interior of the sequence. example for mod (15). 0 2 6 12 5 0 12 11.
%F Prn(i) -= r(i) mod (z) where Prn(i) is the i-th pronic, -= is the congruence sign, r(i) is the i-th residue and mod (z) is the modulus used.
%e r(5) = 7 mod (13).
%K easy,nonn
%O 0,2
%A Stuart M. Ellerstein (ellerstein(AT)aol.com), Nov 17 2005