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.

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A099059 The odd bisection of A000594.

Original entry on oeis.org

1, 252, 4830, -16744, -113643, 534612, -577738, 1217160, -6905934, 10661420, -4219488, 18643272, -25499225, -73279080, 128406630, -52843168, 134722224, -80873520, -182213314, -145589976, 308120442, -17125708, -548895690, 2687348496, -1696965207, -1740295368, -1596055698
Offset: 0

Views

Author

N. J. A. Sloane, Nov 15 2004

Keywords

Examples

			G.f. = 1 + 252*x + 4830*x^2 - 16744*x^3 - 113643*x^4 + 534612*x^5 + ...
G.f. = q + 252*q^3 + 4830*q^5 - 16744*q^7 - 113643*q^9 + 534612*q^11 + ...
		

Crossrefs

Programs

  • Mathematica
    a[ n_] := SeriesCoefficient[ q QPochhammer[q]^24, {q, 0, 2 n + 1}]; (* Michael Somos, Apr 17 2015 *)
    a[n_] := RamanujanTau[2*n+1]; Array[a, 30, 0] (* Amiram Eldar, Jan 10 2025 *)
  • PARI
    {a(n) = if( n<0, 0, n = 2*n+1; polcoeff( x * eta(x + x * O(x^n))^24, n))}; /* Michael Somos, Apr 17 2015 */

Formula

Expansion of (F(q) - F(-q)) / 2 = F(q) + 24*F(q^2) + 2048*F(q^4) in powers of q^2 where F() is the g.f. of A000594. - Michael Somos, Apr 17 2015
a(n) = A000594(2*n + 1). - Michael Somos, Apr 17 2015

Extensions

More terms from Joshua Zucker, May 15 2006

A099060 The even bisection of A000594.

Original entry on oeis.org

-24, -1472, -6048, 84480, -115920, -370944, 401856, 987136, 2727432, -7109760, -12830688, 21288960, 13865712, 24647168, -29211840, -196706304, 165742416, 167282496, -255874080, 408038400, 101267712, -786948864, -447438528, 248758272, 611981400, 850430336, 1758697920
Offset: 1

Views

Author

N. J. A. Sloane, Nov 15 2004

Keywords

Examples

			G.f. = -24*x - 1472*x^2 - 6048*x^3 + 84480*x^4 - 115920*x^5 - 370944*x^6 + ...
G.f. = -24*q^2 - 1472*q^4 - 6048*q^6 + 84480*q^8 - 115920*q^10 - 370944*q^12 + ...
		

Crossrefs

Programs

  • Mathematica
    a[ n_] := SeriesCoefficient[ q QPochhammer[q]^24, {q, 0, 2 n}]; (* Michael Somos, Apr 17 2015 *)
    a[n_] := RamanujanTau[2*n]; Array[a, 30] (* Amiram Eldar, Jan 10 2025 *)
  • PARI
    {a(n) = if( n<0, 0, n = 2*n; polcoeff( x * eta(x + x * O(x^n))^24, n))}; /* Michael Somos, Apr 17 2015 */

Formula

a(n) = A000594(2*n). - Michael Somos, Apr 17 2015

Extensions

More terms from Joshua Zucker, May 15 2006

A126814 Ramanujan numbers (A000594) read mod 16.

Original entry on oeis.org

1, 8, 12, 0, 14, 0, 8, 0, 5, 0, 4, 0, 6, 0, 8, 0, 2, 8, 12, 0, 0, 0, 8, 0, 7, 0, 8, 0, 6, 0, 0, 0, 0, 0, 0, 0, 14, 0, 8, 0, 10, 0, 4, 0, 6, 0, 0, 0, 9, 8, 8, 0, 14, 0, 8, 0, 0, 0, 4, 0, 6, 0, 8, 0, 4, 0, 12, 0, 0, 0, 8, 0, 10, 0, 4, 0, 0, 0, 0, 0, 9, 0, 12, 0, 12, 0, 8, 0, 10, 0, 0, 0, 0, 0, 8, 0, 2, 8, 4, 0
Offset: 1

Views

Author

N. J. A. Sloane, Feb 25 2007

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := Mod[RamanujanTau[n], 16]; Array[a, 100] (* Amiram Eldar, Jan 04 2025 *)
  • PARI
    a(n) = ramanujantau(n) % 16; \\ Amiram Eldar, Jan 04 2025

Formula

a(n) == n^3 * sigma(n) (mod 16) (Rushforth, 1952). - Amiram Eldar, Jan 04 2025

A126816 Ramanujan numbers (A000594) read mod 64.

Original entry on oeis.org

1, 40, 60, 0, 30, 32, 24, 0, 21, 48, 20, 0, 54, 0, 8, 0, 50, 8, 44, 0, 32, 32, 8, 0, 39, 48, 24, 0, 38, 0, 32, 0, 48, 16, 16, 0, 62, 32, 40, 0, 58, 0, 52, 0, 54, 0, 16, 0, 41, 24, 56, 0, 46, 0, 24, 0, 16, 48, 36, 0, 6, 0, 56, 0, 20, 0, 60, 0, 32, 0, 24, 0, 26, 48, 36, 0, 32, 0, 48, 0, 9, 16
Offset: 1

Views

Author

N. J. A. Sloane, Feb 25 2007

Keywords

Crossrefs

Cf. A000594.

Programs

  • Mathematica
    a[n_] := Mod[RamanujanTau[n], 64]; Array[a, 100] (* Amiram Eldar, Jan 05 2025 *)
  • PARI
    a(n) = ramanujantau(n) % 64; \\ Amiram Eldar, Jan 05 2025

A126825 Ramanujan numbers (A000594) read mod 3.

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, Feb 25 2007

Keywords

Crossrefs

Programs

  • Maple
    seq(modp(numtheory:-sigma(n),3)*(1-abs(mods(n-1,3))), n=1..105); # Peter Luschny, Apr 26 2016
  • Mathematica
    Mod[RamanujanTau@ #, 3] & /@ Range@ 105 (* Michael De Vlieger, Apr 26 2016 *)
  • PARI
    a(n) = ramanujantau(n) % 3; \\ Amiram Eldar, Jan 05 2025

Formula

a(4*n) = a(n) (see Corollary 2.2. p. 726 of Ewell link). - Michel Marcus, Dec 23 2012
a(n) = sigma(n) mod 3, for n coprime to 3. - Michel Marcus, Apr 26 2016

A126836 Ramanujan numbers (A000594) read mod 7.

Original entry on oeis.org

1, 4, 0, 5, 0, 0, 0, 4, 2, 0, 1, 0, 0, 0, 0, 3, 0, 1, 0, 0, 0, 4, 4, 0, 4, 0, 0, 0, 2, 0, 0, 3, 0, 0, 0, 3, 4, 0, 0, 0, 0, 0, 2, 5, 0, 2, 0, 0, 0, 2, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 2, 1, 0, 2, 0, 0, 0, 0, 4, 0, 4, 0, 0, 0, 0, 1, 0, 4, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 2, 6, 0, 0, 0, 0, 0
Offset: 1

Views

Author

N. J. A. Sloane, Feb 25 2007

Keywords

Crossrefs

Cf. this sequence (mod 7^1), A126837 (mod 7^2), A126838 (mod 7^3).

Programs

  • Mathematica
    Mod[RamanujanTau@ #, 7] &@ Range@ 120 (* Michael De Vlieger, Apr 25 2016 *)
  • PARI
    a(n) = ramanujantau(n) % 7; \\ Amiram Eldar, Jan 05 2025

Formula

a(n) = n*sigma_3(n) mod 7. - Michel Marcus, Apr 25 2016

A126837 Ramanujan numbers (A000594) read mod 7^2.

Original entry on oeis.org

1, 25, 7, 47, 28, 28, 14, 4, 37, 14, 22, 35, 21, 7, 0, 31, 28, 43, 0, 42, 0, 11, 46, 28, 32, 35, 28, 21, 23, 0, 0, 31, 7, 14, 0, 24, 46, 0, 0, 14, 14, 0, 37, 5, 7, 23, 42, 21, 0, 16, 0, 7, 36, 14, 28, 7, 0, 36, 42, 0, 14, 0, 28, 7, 0, 28, 15, 42, 28, 0, 2, 1, 14, 23, 28, 0, 14, 0, 39, 35, 46
Offset: 1

Views

Author

N. J. A. Sloane, Feb 25 2007

Keywords

Crossrefs

Cf. A000594, A013957, A126836 (mod 7^1), this sequence (mod 7^2), A126838 (mod 7^3).

Programs

  • Mathematica
    a[n_] := Mod[RamanujanTau[n], 49]; Array[a, 100] (* Amiram Eldar, Jan 05 2025 *)
  • PARI
    a(n) = ramanujantau(n) % 49; \\ Amiram Eldar, Jan 05 2025

Formula

a(n) == n * sigma_9(n) (mod 7^2) if Legendre symbol (n,7) = A175629(n) = -1 (Kolberg, 1962). - Amiram Eldar, Jan 05 2025

A126838 Ramanujan numbers (A000594) read mod 7^3.

Original entry on oeis.org

1, 319, 252, 243, 28, 126, 63, 102, 233, 14, 218, 182, 217, 203, 196, 325, 28, 239, 294, 287, 98, 256, 193, 322, 81, 280, 126, 217, 121, 98, 98, 80, 56, 14, 49, 24, 291, 147, 147, 112, 112, 49, 282, 152, 7, 170, 91, 266, 196, 114, 196, 252, 134, 63, 273, 252, 0, 183, 42
Offset: 1

Views

Author

N. J. A. Sloane, Feb 25 2007

Keywords

Crossrefs

Cf. A000594, A126836 (mod 7^1), A126837 (mod 7^2), this sequence (mod 7^3).

Programs

  • Mathematica
    a[n_] := Mod[RamanujanTau[n], 343]; Array[a, 100] (* Amiram Eldar, Jan 05 2025 *)
  • PARI
    a(n) = ramanujantau(n) % 343; \\ Amiram Eldar, Jan 05 2025

A126840 Ramanujan numbers (A000594) read mod 11^2.

Original entry on oeis.org

1, 97, 10, 101, 111, 2, 75, 22, 97, 119, 34, 42, 37, 15, 21, 18, 20, 92, 110, 79, 24, 31, 76, 99, 73, 80, 93, 73, 99, 101, 73, 8, 98, 4, 97, 117, 102, 22, 7, 22, 113, 29, 27, 46, 119, 112, 85, 59, 19, 63, 79, 107, 5, 67, 23, 77, 11, 44, 82, 64, 23, 63, 15, 91, 114, 68, 59, 84, 34
Offset: 1

Views

Author

N. J. A. Sloane, Feb 25 2007

Keywords

Crossrefs

Cf. A000594, A126839 (mod 11^1), this sequence (mod 11^2), A126841 (mod 11^3).

Programs

  • Mathematica
    a[n_] := Mod[RamanujanTau[n], 121]; Array[a, 100] (* Amiram Eldar, Jan 05 2025 *)
  • PARI
    a(n) = ramanujantau(n) % 121; \\ Amiram Eldar, Jan 05 2025

A126841 Ramanujan numbers (A000594) read mod 11^3.

Original entry on oeis.org

1, 1307, 252, 1190, 837, 607, 559, 627, 823, 1208, 881, 405, 1247, 1225, 626, 865, 625, 213, 110, 442, 1113, 152, 1286, 946, 73, 685, 456, 1041, 1067, 948, 194, 855, 1066, 972, 702, 1085, 586, 22, 128, 385, 597, 1239, 269, 893, 724, 1080, 932, 1027, 1229, 910, 442
Offset: 1

Views

Author

N. J. A. Sloane, Feb 25 2007

Keywords

Crossrefs

Cf. A000594, A126839 (mod 11^1), A126840 (mod 11^2), this sequence (mod 11^3).

Programs

  • Mathematica
    a[n_] := Mod[RamanujanTau[n], 1331]; Array[a, 100] (* Amiram Eldar, Jan 05 2025 *)
  • PARI
    a(n) = ramanujantau(n) % 1331; \\ Amiram Eldar, Jan 05 2025
Previous Showing 31-40 of 208 results. Next