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 1-7 of 7 results.

A131852 Imaginary part of the function z defined in A131851.

Original entry on oeis.org

0, 0, 1, 1, 0, 0, 1, 1, -1, -1, 0, 0, -1, -1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, -1, -1, 0, 0, -1, -1, 0, 0, 1, 1, 2, 2, 1, 1, 2, 2, 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 2, 2, 1, 1, 2, 2, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, -1, -1, 0, 0, -1, -1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, -1, -1, 0, 0, -1, -1, 0, 0, 1, 1, 2, 2, 1, 1, 2, 2, 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 2, 2, 1, 1, 2, 2, 0
Offset: 0

Views

Author

Reinhard Zumkeller, Jul 22 2007

Keywords

Comments

a(A000079(n)) = A056594(n+3);
a(A131855(n)) = 0; a(A131862(n)) > 0; a(A131857(n)) = 1; a(A131864(n)) < 0;
for n > 0: a(A098704(n+1)) = n and abs(a(m)) < n for m < A098704(n+1).

Programs

  • Mathematica
    z[0] = 0; z[n_] := z[n] = z[Floor[n/2]]*I + Mod[n, 2]; Table[z[n] // Im, {n, 0, 120}] (* Jean-François Alcover, Mar 02 2019 *)

A131853 Numbers m such that z(m)=(0,0) with z as defined in A131851.

Original entry on oeis.org

0, 5, 10, 15, 20, 30, 40, 45, 60, 65, 75, 80, 85, 90, 95, 105, 120, 125, 130, 135, 150, 160, 165, 170, 175, 180, 190, 195, 210, 215, 225, 235, 240, 245, 250, 255, 260, 270, 300, 320, 325, 330, 335, 340, 350, 360, 365, 380, 390, 420, 430, 450, 455, 470, 480, 485
Offset: 1

Views

Author

Reinhard Zumkeller, Jul 22 2007

Keywords

Comments

Intersection of A131854 and A131855: A131851(a(n))=0, A131852(a(n))=0;
conjecture: a(n) mod 5 = 0.

Crossrefs

Programs

  • Mathematica
    z[n_] := z[n] = If[n == 0, 0, z[Floor[n/2]] I + Mod[n, 2]];
    Flatten[Position[Table[z[n], {n, 0, 500}], 0] - 1] (* Jean-François Alcover, Oct 12 2021 *)

A131854 Numbers m such that A131851(m) = 0.

Original entry on oeis.org

0, 2, 5, 7, 8, 10, 13, 15, 20, 22, 28, 30, 32, 34, 37, 39, 40, 42, 45, 47, 52, 54, 60, 62, 65, 67, 73, 75, 80, 82, 85, 87, 88, 90, 93, 95, 97, 99, 105, 107, 112, 114, 117, 119, 120, 122, 125, 127, 128, 130, 133, 135, 136, 138, 141, 143, 148, 150, 156, 158, 160, 162, 165
Offset: 1

Views

Author

Reinhard Zumkeller, Jul 22 2007

Keywords

Crossrefs

Programs

  • Maple
    Z:= proc(n) option remember;
    I*procname(floor(n/2))+(n mod 2)
    end proc:
    Z(0):= 0:
    select(Re@Z=0, [$0..1000]); # Robert Israel, Dec 18 2017
  • Mathematica
    z[0] = 0; z[n_] := z[n] = z[Floor[n/2]]*I + Mod[n, 2]; Select[Range[0, 200], Re[z[#]] == 0&] (* Jean-François Alcover, Jan 31 2018 *)
  • PARI
    isok(n) = {d = Vecrev(binary(n)); real(sum(k=1, #d, d[k]*I^(k-1))) == 0;} \\ Michel Marcus, Jan 31 2018

A131857 Numbers m such that A131852(m) = 1.

Original entry on oeis.org

2, 3, 6, 7, 18, 19, 22, 23, 32, 33, 36, 37, 42, 43, 46, 47, 48, 49, 52, 53, 58, 59, 62, 63, 66, 67, 70, 71, 82, 83, 86, 87, 96, 97, 100, 101, 106, 107, 110, 111, 112, 113, 116, 117, 122, 123, 126, 127, 162, 163, 166, 167, 178, 179, 182, 183, 226, 227, 230, 231, 242, 243
Offset: 1

Views

Author

Reinhard Zumkeller, Jul 22 2007

Keywords

Crossrefs

Programs

  • Maple
    Z:= proc(n) option remember;
    I*procname(floor(n/2))+(n mod 2)
    end proc:
    Z(0):= 0:
    select(Im@Z=1, [$0..1000]); # Robert Israel, Dec 18 2017
  • Mathematica
    z[0] = 0; z[n_] := z[n] = z[Floor[n/2]]*I + Mod[n, 2]; Select[Range[0, 250], Im[z[#]] == 1&] (* Jean-François Alcover, Jan 31 2018 *)
  • PARI
    isok(n) = {d = Vecrev(binary(n)); imag(sum(k=1, #d, d[k]*I^(k-1))) == 1;} \\ Michel Marcus, Jan 31 2018

A131858 Numbers m such that z(m)=(1,0) with z as defined in A131851.

Original entry on oeis.org

1, 11, 16, 21, 26, 31, 41, 56, 61, 81, 91, 121, 131, 146, 151, 161, 171, 176, 181, 186, 191, 211, 241, 251, 256, 261, 266, 271, 276, 286, 296, 301, 316, 321, 331, 336, 341, 346, 351, 361, 376, 381, 386, 391, 406, 416, 421, 426, 431, 436, 446, 451, 466, 471
Offset: 1

Views

Author

Reinhard Zumkeller, Jul 22 2007

Keywords

Comments

Intersection of A131855 and A131859: A131851(a(n))=1, A131852(a(n))=0.

Crossrefs

A131862 Numbers m such that A131852(m) > 0.

Original entry on oeis.org

2, 3, 6, 7, 18, 19, 22, 23, 32, 33, 34, 35, 36, 37, 38, 39, 42, 43, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 58, 59, 62, 63, 66, 67, 70, 71, 82, 83, 86, 87, 96, 97, 98, 99, 100, 101, 102, 103, 106, 107, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 122, 123, 126, 127
Offset: 1

Views

Author

Reinhard Zumkeller, Jul 22 2007

Keywords

Crossrefs

A131864 Numbers m such that A131852(m) < 0.

Original entry on oeis.org

8, 9, 12, 13, 24, 25, 28, 29, 72, 73, 76, 77, 88, 89, 92, 93, 128, 129, 132, 133, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 148, 149, 152, 153, 154, 155, 156, 157, 158, 159, 168, 169, 172, 173, 184, 185, 188, 189, 192, 193, 196, 197, 200, 201, 202, 203
Offset: 1

Views

Author

Reinhard Zumkeller, Jul 22 2007

Keywords

Crossrefs

Showing 1-7 of 7 results.