A165916 -id:A165916 - cp's OEIS frontend

A165917 a(n) = sum of the squarefree quadratic non-residues of n.

0, 0, 2, 5, 5, 7, 14, 23, 16, 12, 25, 44, 31, 37, 55, 86, 56, 73, 57, 117, 100, 95, 141, 188, 117, 86, 143, 193, 138, 172, 216, 287, 233, 161, 251, 393, 231, 264, 403, 520, 319, 390, 328, 571, 552, 398, 509, 706, 442, 422, 489, 731, 429, 581, 707, 898, 657, 477

Offset: 1

Christopher Hunt Gribble, Sep 30 2009

nonn

C. H. Gribble, Table of n, a(n) for n=1,...,1000.

Cf. A165916

a(1) added and definition corrected by Christopher Hunt Gribble, Oct 05 2009

A165918 a(n) = number of squarefree quadratic non-residues of n.

Original entry on oeis.org

0, 0, 1, 2, 2, 2, 3, 5, 4, 3, 4, 7, 5, 5, 7, 10, 7, 8, 6, 11, 10, 8, 10, 15, 10, 8, 11, 15, 10, 12, 12, 18, 15, 11, 15, 21, 13, 13, 19, 25, 16, 19, 14, 25, 24, 17, 19, 29, 19, 18, 21, 28, 17, 22, 25, 33, 25, 18, 19, 35, 21, 22, 32, 34, 28, 29, 20, 36, 33, 31, 29, 44, 26, 23

Offset: 1

Christopher Hunt Gribble, Sep 30 2009

nonn

C. H. Gribble, Table of n, a(n) for n=1,...,1000.

Cf. A165916.

squares(n) = {local(s = Set()); for (j=1, n, s = setunion(s, Set(j^2 % n));); return (s);}
qnonr(n) = {local(s = Set()); sq = squares(n);for (j=0, n-1, if (length(setintersect(Set(j), sq))==0, s = setunion(s, Set(j)));); return (s);}
a(n) = {s = Set(); qnr = qnonr(n); for (j=1, #qnr, if (issquarefree(eval(qnr[j])), s = setunion(s, Set(qnr[j])));); return (#s);}  \\ Michel Marcus, Jul 23 2013

a(1) added by Christopher Hunt Gribble, Oct 05 2009

cp's OEIS Frontend

A165917 a(n) = sum of the squarefree quadratic non-residues of n.

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