A215284 Numbers m such that Sum_{k=1..m} (m - k | k) = 0, where (i|j) is the Kronecker symbol.

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

Offset

1,1

Comments

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

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..2830 from Robert Israel)

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-François 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]
(PARI) is(m) = sum(k = 1, m, kronecker(m-k, k)) == 0; \\ Amiram Eldar, Nov 07 2024

Crossrefs

Cf. A215200, A215283, A215285.

Sequence in context: A314409 A314410 A222802 * A325438 A314411 A359353

Adjacent sequences: A215281 A215282 A215283 * A215285 A215286 A215287

Keyword

nonn

Author

Peter Luschny, Aug 07 2012

Status

approved