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 1-3 of 3 results.

A309125 a(n) = n + 2^2 * floor(n/2^2) + 3^2 * floor(n/3^2) + 4^2 * floor(n/4^2) + ...

Original entry on oeis.org

1, 2, 3, 8, 9, 10, 11, 16, 26, 27, 28, 33, 34, 35, 36, 57, 58, 68, 69, 74, 75, 76, 77, 82, 108, 109, 119, 124, 125, 126, 127, 148, 149, 150, 151, 201, 202, 203, 204, 209, 210, 211, 212, 217, 227, 228, 229, 250, 300, 326, 327, 332, 333, 343, 344, 349, 350, 351, 352, 357, 358, 359, 369, 454, 455, 456
Offset: 1

Views

Author

Ilya Gutkovskiy, Jul 13 2019

Keywords

Comments

Partial sums of A035316.

Crossrefs

Programs

  • Mathematica
    Table[Sum[k^2 Floor[n/k^2], {k, 1, n}], {n, 1, 66}]
    nmax = 66; CoefficientList[Series[1/(1 - x) Sum[k^2 x^(k^2)/(1 - x^(k^2)), {k, 1, Floor[nmax^(1/2)] + 1}], {x, 0, nmax}], x] // Rest
  • PARI
    a(n) = sum(k=1, n, k^2*(n\k^2)); \\ Seiichi Manyama, Aug 30 2021

Formula

G.f.: (1/(1 - x)) * Sum_{k>=1} k^2 * x^(k^2)/(1 - x^(k^2)).
a(n) ~ zeta(3/2)*n^(3/2)/3 - n/2. - Vaclav Kotesovec, Aug 30 2021

A309127 a(n) = n + 2^4 * floor(n/2^4) + 3^4 * floor(n/3^4) + 4^4 * floor(n/4^4) + ...

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139
Offset: 1

Views

Author

Ilya Gutkovskiy, Jul 13 2019

Keywords

Comments

Partial sums of A300909.

Crossrefs

Programs

  • Mathematica
    Table[Sum[k^4 Floor[n/k^4], {k, 1, n}], {n, 1, 75}]
    nmax = 75; CoefficientList[Series[1/(1 - x) Sum[k^4 x^(k^4)/(1 - x^(k^4)), {k, 1, Floor[nmax^(1/4)] + 1}], {x, 0, nmax}], x] // Rest
  • PARI
    a(n) = sum(k=1, n, k^4*(n\k^4)); \\ Seiichi Manyama, Aug 30 2021

Formula

G.f.: (1/(1 - x)) * Sum_{k>=1} k^4 * x^(k^4)/(1 - x^(k^4)).
a(n) ~ zeta(5/4)*n^(5/4)/5 - n/2. - Vaclav Kotesovec, Aug 30 2021

A347397 a(n) = Sum_{k=1..n} k^k * floor(n/k^k).

Original entry on oeis.org

1, 2, 3, 8, 9, 10, 11, 16, 17, 18, 19, 24, 25, 26, 27, 32, 33, 34, 35, 40, 41, 42, 43, 48, 49, 50, 78, 83, 84, 85, 86, 91, 92, 93, 94, 99, 100, 101, 102, 107, 108, 109, 110, 115, 116, 117, 118, 123, 124, 125, 126, 131, 132, 160, 161, 166, 167, 168, 169, 174, 175, 176, 177, 182, 183, 184
Offset: 1

Views

Author

Seiichi Manyama, Aug 30 2021

Keywords

Comments

What is the limit_{n->infinity} a(n) / (n*log(n)/LambertW(log(n))) ?. - Vaclav Kotesovec, Aug 30 2021

Crossrefs

Programs

  • Mathematica
    Table[Sum[k^k*Floor[n/k^k], {k, 1, n}], {n, 1, 100}] (* Vaclav Kotesovec, Aug 30 2021 *)
  • PARI
    a(n) = sum(k=1, n, k^k*(n\k^k));

Formula

G.f.: (1/(1 - x)) * Sum_{k>=1} k^k * x^(k^k)/(1 - x^(k^k)).
Showing 1-3 of 3 results.