A020649 - OEIS

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A020649

Least nonresidue of n.

2, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 3, 2, 2, 3, 2, 2, 2, 2, 2, 5, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 3, 2, 2, 2, 2, 2, 2, 3, 2, 2, 2, 2, 5, 5, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 7, 2, 5, 2, 2, 2, 2, 2, 3, 2, 2, 3, 2, 2, 2, 2, 2, 2, 3, 2, 2, 2, 2, 5, 2, 2, 5, 3, 2, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2 (list; graph; refs; listen; history; internal format)

	OFFSET	`3,1`
	LINKS	`Eric Weisstein's World of Mathematics, Quadratic Nonresidue`
	PROG	`Contribution from Michael B. Porter (michael_b_porter(AT)yahoo.com), Apr 30 2010: (Start)` `(PARI) residue(n, m)={local(r); r=0; for(i=0, floor(m/2), if(i^2%m==n, r=1)); r}` `A020649(n)={local(r, m); r=0; m=0; while(r==0, m=m+1; if(!residue(m, n), r=1)); m} (End)`
	CROSSREFS	`Sequence in context: A096859 A005086 A157372 * A183024 A067131 A094915` `Adjacent sequences: A020646 A020647 A020648 * A020650 A020651 A020652`
	KEYWORD	`nonn`
	AUTHOR	`David W. Wilson (davidwwilson(AT)comcast.net)`

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Last modified February 15 05:45 EST 2012. Contains 205694 sequences.