A025025 Numbers whose least quadratic nonresidue (A020649) is 13.

479, 958, 1151, 1319, 2302, 2351, 2638, 2689, 3529, 3671, 3911, 4702, 4751, 4919, 5378, 5519, 5569, 6599, 7058, 7342, 7559, 7561, 7681, 7822, 8951, 9241, 9502, 9601, 9719, 9769, 9838, 11038, 11138, 12049, 12239, 12721, 12911, 13151, 13198, 14159

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Quadratic Nonresidue.

Mathematica

Select[Range[14000], Min @ Complement[Range[# - 1], Mod[Range[#/2]^2, #]] == 13 &] (* Amiram Eldar, Oct 31 2020 *)

Prog

(PARI) residue(n, m)=local(r); r=0; for(i=1, floor(m/2), if(i^2%m==n, r=1)); r
isA025025(n)=local(a); a=1; forprime(p=2, 11, a=a && residue(p, n)); a=a && !residue(13, n); a \\ Michael B. Porter, Apr 30 2010
(PARI) is(n)=issquare(Mod(2, n)) && issquare(Mod(3, n)) && issquare(Mod(5, n)) && issquare(Mod(7, n)) && issquare(Mod(11, n)) && !issquare(Mod(13, n)) \\ Charles R Greathouse IV, Jan 24 2020

Crossrefs

Cf. A020649, A025020, A025021, A025022, A025023, A025024, A025026, A025027, A025028, A025029.

Sequence in context: A186950 A056987 A323051 * A108256 A262222 A115157

Adjacent sequences: A025022 A025023 A025024 * A025026 A025027 A025028

Keyword

nonn

Author

David W. Wilson

Status

approved