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 1-6 of 6 results.

A359324 Number of divisors of 6*n-2 of form 6*k+5.

Original entry on oeis.org

0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 2, 0, 1, 1, 1, 1, 1, 0, 1, 0, 2, 1, 1, 0, 2, 1, 1, 0, 1, 1, 2, 0, 1, 0, 1, 2, 1, 1, 2, 0, 2, 0, 1, 0, 1, 2, 2, 0, 1, 0, 2, 0, 2, 1, 1, 2, 1, 1, 1, 0, 2, 1, 1, 0, 1, 1, 2, 0, 2, 1, 2, 0, 2, 0, 1, 2, 1, 1, 1, 1, 3, 0, 1, 0, 1, 2, 1, 0, 1
Offset: 1

Views

Author

Seiichi Manyama, Dec 25 2022

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := DivisorSum[6*n-2, 1 &, Mod[#, 6] == 5 &]; Array[a, 100] (* Amiram Eldar, Aug 14 2023 *)
  • PARI
    a(n) = sumdiv(6*n-2, d, d%6==5);
    
  • PARI
    my(N=100, x='x+O('x^N)); concat(0, Vec(sum(k=1, N, x^(2*k)/(1-x^(6*k-1)))))
    
  • PARI
    my(N=100, x='x+O('x^N)); concat(0, Vec(sum(k=1, N, x^(5*k-3)/(1-x^(6*k-4)))))

Formula

a(n) = A319995(6*n-2).
G.f.: Sum_{k>0} x^(2*k)/(1 - x^(6*k-1)).
G.f.: Sum_{k>0} x^(5*k-3)/(1 - x^(6*k-4)).

A359287 Number of divisors of 5*n-1 of form 5*k+2.

Original entry on oeis.org

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

Views

Author

Seiichi Manyama, Dec 24 2022

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := DivisorSum[5*n-1, 1 &, Mod[#, 5] == 2 &]; Array[a, 100] (* Amiram Eldar, Aug 16 2023 *)
  • PARI
    a(n) = sumdiv(5*n-1, d, d%5==2);
    
  • PARI
    my(N=100, x='x+O('x^N)); Vec(sum(k=1, N, x^(2*k-1)/(1-x^(5*k-3))))

Formula

a(n) = A001877(5*n-1).
G.f.: Sum_{k>0} x^(2*k-1)/(1 - x^(5*k-3)).

A363025 Sum of divisors of 5*n-2 of form 5*k+2.

Original entry on oeis.org

0, 2, 0, 2, 0, 9, 0, 2, 0, 14, 0, 2, 7, 19, 0, 2, 0, 24, 0, 9, 0, 41, 0, 2, 0, 34, 7, 2, 0, 39, 17, 2, 0, 63, 0, 2, 0, 49, 0, 24, 7, 54, 0, 2, 0, 71, 0, 26, 27, 64, 0, 2, 0, 69, 7, 2, 0, 118, 0, 2, 0, 108, 0, 2, 17, 84, 37, 2, 7, 101, 0, 2, 0, 94, 0, 78, 0, 99, 0, 2, 0, 133, 7, 24, 47, 109, 0, 2, 0, 153, 0
Offset: 1

Views

Author

Seiichi Manyama, Jul 06 2023

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := DivisorSum[5*n - 2, # &, Mod[#, 5] == 2 &]; Array[a, 100] (* Amiram Eldar, Jul 06 2023 *)
  • PARI
    a(n) = sumdiv(5*n-2, d, (d%5==2)*d);

Formula

a(n) = A284280(5*n-2).
G.f.: Sum_{k>0} (5*k-3) * x^(4*k-2) / (1 - x^(5*k-3)).

A364101 Sum of divisors of 5*n-2 of form 5*k+4.

Original entry on oeis.org

0, 4, 0, 9, 0, 18, 0, 19, 0, 28, 0, 29, 9, 38, 0, 39, 0, 48, 0, 63, 0, 67, 0, 59, 0, 68, 19, 69, 0, 78, 9, 79, 0, 126, 0, 89, 0, 98, 0, 108, 29, 108, 0, 109, 0, 137, 0, 167, 9, 128, 0, 129, 0, 138, 39, 139, 0, 181, 0, 149, 0, 216, 0, 159, 19, 168, 9, 169, 49, 207, 0, 179, 0, 188, 0, 266, 0, 198, 0
Offset: 1

Views

Author

Seiichi Manyama, Jul 04 2023

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := DivisorSum[5*n - 2, # &, Mod[#, 5] == 4 &]; Array[a, 100] (* Amiram Eldar, Jul 17 2023 *)
  • PARI
    a(n) = sumdiv(5*n-2, d, (d%5==4)*d);

Formula

a(n) = A284103(5*n-2).
G.f.: Sum_{k>0} (5*k-1) * x^(2*k) / (1 - x^(5*k-1)).

A364105 Expansion of Sum_{k>0} k * x^(2*k) / (1 - x^(5*k-1)).

Original entry on oeis.org

0, 1, 0, 2, 0, 4, 0, 4, 0, 6, 0, 6, 2, 8, 0, 8, 0, 10, 0, 13, 0, 14, 0, 12, 0, 14, 4, 14, 0, 16, 2, 16, 0, 26, 0, 18, 0, 20, 0, 22, 6, 22, 0, 22, 0, 28, 0, 34, 2, 26, 0, 26, 0, 28, 8, 28, 0, 37, 0, 30, 0, 44, 0, 32, 4, 34, 2, 34, 10, 42, 0, 36, 0, 38, 0, 54, 0, 40, 0, 40, 0, 54, 12, 46, 2, 44, 0, 44, 0
Offset: 1

Views

Author

Seiichi Manyama, Jul 05 2023

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := DivisorSum[5*n - 2, # + 1 &, Mod[#, 5] == 4 &]/5; Array[a, 100] (* Amiram Eldar, Jul 12 2023 *)
  • PARI
    a(n) = sumdiv(5*n-2, d, (d%5==4)*(d+1))/5;

Formula

a(n) = (1/5) * Sum_{d | 5*n-2, d==4 (mod 5)} (d+1).
G.f.: Sum_{k>0} x^(4*k-2) / (1 - x^(5*k-3))^2.

A363029 Expansion of Sum_{k>0} k * x^(4*k-2) / (1 - x^(5*k-3)).

Original entry on oeis.org

0, 1, 0, 1, 0, 3, 0, 1, 0, 4, 0, 1, 2, 5, 0, 1, 0, 6, 0, 3, 0, 10, 0, 1, 0, 8, 2, 1, 0, 9, 4, 1, 0, 15, 0, 1, 0, 11, 0, 6, 2, 12, 0, 1, 0, 16, 0, 7, 6, 14, 0, 1, 0, 15, 2, 1, 0, 26, 0, 1, 0, 24, 0, 1, 4, 18, 8, 1, 2, 22, 0, 1, 0, 20, 0, 18, 0, 21, 0, 1, 0, 29, 2, 6, 10, 23, 0, 1, 0, 33, 0, 1, 0
Offset: 1

Views

Author

Seiichi Manyama, Jul 06 2023

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := DivisorSum[5*n - 2, # + 3 &, Mod[#, 5] == 2 &]/5; Array[a, 100] (* Amiram Eldar, Jul 06 2023 *)
  • PARI
    a(n) = sumdiv(5*n-2, d, (d%5==2)*(d+3))/5;

Formula

a(n) = (1/5) * Sum_{d | 5*n-2, d==2 (mod 5)} (d+3).
G.f.: Sum_{k>0} x^(2*k) / (1 - x^(5*k-1))^2.
Showing 1-6 of 6 results.