cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-5 of 5 results.

A374188 Array read by ascending antidiagonals: b is a term of row A(a) if and only if K(a/b) != K(A374157(b)/a), where K denotes the Kronecker symbol (A372728), and a = 4*n - 1 for some n >= 1.

Original entry on oeis.org

2, 2, 10, 2, 10, 26, 2, 10, 12, 28, 2, 26, 12, 18, 34, 2, 10, 28, 18, 24, 44, 2, 10, 12, 34, 24, 26, 50, 2, 10, 12, 18, 44, 26, 34, 56, 2, 10, 26, 18, 24, 56, 28, 44, 58, 2, 12, 12, 28, 24, 26, 58, 34, 48, 74, 2, 10, 18, 18, 34, 26, 28, 74, 42, 50, 76
Offset: 1

Views

Author

Peter Luschny, Jun 30 2024

Keywords

Comments

We say two integers, a and b, are related by the golden theorem (Gauss) if K(a/b) = K(A374157(b)/a), an identity, that is valid for all whole numbers a (A001057) and all odd numbers b (A005408). This fact is equivalent to the law of quadratic reciprocity and its first and second supplement. See A372728 (Kronecker) and A373223 (Gauss) for details and examples. Here, we complement this by looking at pairs of integers that do not obey this law.

Examples

			  [n] [ a] b ...
  [1] [ 3] 2, 10, 26, 28, 34, 44, 50, 56, 58, 74, 76, 82, ...  A374180
  [2] [ 7] 2, 10, 12, 18, 24, 26, 34, 44, 48, 50, 58, 60, ...  A374181
  [3] [11] 2, 10, 12, 18, 24, 26, 28, 34, 42, 48, 50, 56, ...  A374182
  [4] [15] 2, 26, 28, 34, 44, 56, 58, 74, 76, 82, 88, 92, ...  A374183
  [5] [19] 2, 10, 12, 18, 24, 26, 28, 34, 42, 44, 48, 50, ...  A374184
  [6] [23] 2, 10, 12, 18, 24, 26, 28, 34, 42, 44, 48, 50, ...
  [7] [27] 2, 10, 26, 28, 34, 44, 50, 56, 58, 74, 76, 82, ...
  [8] [31] 2, 10, 12, 18, 24, 26, 28, 34, 42, 44, 48, 50, ...
		

Crossrefs

Rows: A374180 [1], A374181 [2], A374182 [3], A374183 [4], A374184 [5].
Cf. A374189 (seen as set), A372728 (Kronecker), A373223 (Gauss), A374157, A004767.

Programs

  • Maple
    KS := (a, n) -> NumberTheory:-KroneckerSymbol(a, n):
    A374157 := n -> ifelse(iquo(n, 2)::even, n, -n):
    A374188_row := (a, len) -> local n; select(n -> (KS(a, n) <> KS(A374157(n), a)), [seq(0..len)]): seq(print(A374188_row(4*m - 1, 350)), m = 1..5);
  • SageMath
    def A374157(n): return (-1)**(n // 2)*n
    def ks(a, n): return kronecker_symbol(a, n)
    def ksp(a, len): return [n for n in range(len) if ks(a, n) != ks(A374157(n), a)]
    def A374188_row(n, len): return ksp(4*n - 1, len)
    for m in range(1, 8): print(A374188_row(m, 100)[:12])

Formula

All terms are even.

A374180 Numbers k such that K(3 / k) != K((-1)^floor(k/2)*k / 3), where K(a/b) is the Kronecker symbol. Row 1 of A374188.

Original entry on oeis.org

2, 10, 26, 28, 34, 44, 50, 56, 58, 74, 76, 82, 88, 92, 98, 106, 112, 122, 124, 130, 140, 146, 152, 154, 170, 172, 176, 178, 184, 188, 194, 202, 218, 220, 224, 226, 236, 242, 248, 250, 266, 268, 274, 280, 284, 290, 298, 304, 314, 316, 322, 332, 338, 344, 346
Offset: 1

Views

Author

Peter Luschny, Jun 30 2024

Keywords

Crossrefs

Cf. A372728 (Kronecker).

Programs

A374181 Numbers k such that K(7 / k) != K((-1)^floor(k/2)*k / 7), where K(a/b) is the Kronecker symbol. Row 2 of A374188.

Original entry on oeis.org

2, 10, 12, 18, 24, 26, 34, 44, 48, 50, 58, 60, 66, 74, 76, 82, 88, 90, 92, 96, 106, 108, 114, 120, 122, 124, 130, 138, 146, 152, 156, 162, 170, 172, 176, 178, 184, 186, 188, 192, 194, 202, 204, 216, 218, 220, 226, 234, 236, 240, 242, 248, 250, 258, 268, 274
Offset: 1

Views

Author

Peter Luschny, Jun 30 2024

Keywords

Crossrefs

Cf. A372728 (Kronecker).

Programs

A374182 Numbers k such that K(11 / k) != K((-1)^floor(k/2)*k / 11), where K(a/b) is the Kronecker symbol. Row 3 of A374188.

Original entry on oeis.org

2, 10, 12, 18, 24, 26, 28, 34, 42, 48, 50, 56, 58, 60, 74, 76, 82, 90, 92, 96, 98, 106, 108, 112, 114, 120, 122, 124, 130, 138, 140, 146, 152, 156, 162, 170, 172, 178, 184, 186, 188, 192, 194, 202, 204, 210, 216, 218, 224, 226, 234, 236, 240, 248, 250, 252
Offset: 1

Views

Author

Peter Luschny, Jun 30 2024

Keywords

Crossrefs

Cf. A372728 (Kronecker).

Programs

A374183 Numbers k such that K(15 / k) != K((-1)^floor(k/2)*k / 15), where K(a/b) is the Kronecker symbol. Row 4 of A374188.

Original entry on oeis.org

2, 26, 28, 34, 44, 56, 58, 74, 76, 82, 88, 92, 98, 106, 112, 122, 124, 146, 152, 154, 172, 176, 178, 184, 188, 194, 202, 218, 224, 226, 236, 242, 248, 266, 268, 274, 284, 298, 304, 314, 316, 322, 332, 338, 344, 346, 352, 362, 364, 368, 376, 386, 394, 412, 418
Offset: 1

Views

Author

Peter Luschny, Jun 30 2024

Keywords

Crossrefs

Cf. A372728 (Kronecker).

Programs

Showing 1-5 of 5 results.