

A215284


n such that Sum_{k=1..n} (n  k  k) = 0, where (ij) 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
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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(nk, 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 & ] (* JeanFrançois Alcover, Jul 29 2013 *)


PROG

(Sage)
def A215200_row(n): return [kronecker_symbol(nk, 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



