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A111658 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. 0
0, 2, 6, 12, 7, 4, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

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.

LINKS

Table of n, a(n) for n=0..6.

FORMULA

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.

EXAMPLE

r(5) = 7 mod (13).

CROSSREFS

Sequence in context: A014965 A074259 A113540 * A105692 A107647 A210842

Adjacent sequences:  A111655 A111656 A111657 * A111659 A111660 A111661

KEYWORD

easy,nonn

AUTHOR

Stuart M. Ellerstein (ellerstein(AT)aol.com), Nov 17 2005

STATUS

approved

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Last modified December 7 03:27 EST 2019. Contains 329836 sequences. (Running on oeis4.)