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A215284 n such that Sum_{k=1..n} (n - k | k) = 0, where (i|j) is the Kronecker symbol. 4
5, 8, 12, 18, 20, 21, 24, 28, 32, 40, 44, 48, 52, 53, 56, 60, 68, 69, 72, 76, 77, 80, 84, 88, 92, 96, 99, 104, 108, 112, 116, 120, 124, 125, 126, 128, 132, 136, 140, 141, 148, 150, 152, 156, 160, 162, 164, 165, 168, 172, 176, 180, 184, 188, 189, 192, 197 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Appears to include all multiples of 4 that are not squares. - Robert Israel, Mar 11 2018

LINKS

Robert Israel, Table of n, a(n) for n = 1..2830

MAPLE

f:= n -> add(numtheory:-jacobi(n-k, k), k=1..n):

select(n -> f(n)=0, [$1..300]); # Robert Israel, Mar 11 2018

MATHEMATICA

Select[ Range[200], Sum[ KroneckerSymbol[# - k, k], {k, 1, #}] == 0 & ] (* Jean-Fran├žois Alcover, Jul 29 2013 *)

PROG

(Sage)

def A215200_row(n): return [kronecker_symbol(n-k, k) for k in (1..n)]

[n for n in (1..197) if sum(A215200_row(n)) == 0]

CROSSREFS

Cf. A215200, A215283, A215285.

Sequence in context: A314409 A314410 A222802 * A325438 A314411 A069102

Adjacent sequences:  A215281 A215282 A215283 * A215285 A215286 A215287

KEYWORD

nonn

AUTHOR

Peter Luschny, Aug 07 2012

STATUS

approved

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Last modified October 20 22:22 EDT 2021. Contains 348119 sequences. (Running on oeis4.)