A071958 Numbers k such that Sum_{i=0..k} K(k, i) < 0 where K(x, y) is the Kronecker symbol (x/y).

67, 99, 115, 147, 163, 187, 267, 275, 283, 307, 315, 355, 379, 403, 427, 475, 507, 523, 531, 595, 619, 643, 675, 747, 763, 787, 883, 907, 931, 947, 955, 975, 1003, 1027, 1107, 1123, 1147, 1179, 1203, 1267, 1275, 1347, 1363, 1387, 1395, 1435, 1467, 1475

Offset: 1

Author

Benoit Cloitre, Jun 16 2002

Keywords

• easy
• nonn

Links

• Robert G. Wilson v, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A071961.

Programs

Mathematica

f[n_] := Sum[ KroneckerSymbol[n, k], {k, 0, n}]; Select[ Range@ 1500, f[#] < 0 &] (* Robert G. Wilson v, Mar 21 2015 *)

PARI

for(n=1, 1800, if(sum(i=0, n, kronecker(n,i)) < 0, print1(n,",")))

SageMath

print([n for n in range(999) if sum(kronecker(n, k)
for k in range(n + 1)) < 0])  # Peter Luschny, May 16 2024

Extensions

Summation range set to {i=0..k} by Peter Luschny, May 16 2024