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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A357071 Number of partitions of n into at most 3 distinct positive triangular numbers.

Original entry on oeis.org

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

Views

Author

Ilya Gutkovskiy, Oct 25 2022

Keywords

Crossrefs

A357072 Number of partitions of n into at most 4 distinct positive triangular numbers.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 2, 1, 0, 1, 1, 1, 2, 1, 1, 2, 1, 2, 2, 0, 2, 3, 1, 1, 3, 2, 1, 4, 3, 0, 3, 2, 2, 4, 3, 3, 3, 1, 3, 3, 2, 4, 5, 4, 1, 5, 3, 2, 6, 3, 3, 6, 4, 2, 5, 4, 4, 5, 4, 2, 7, 5, 5, 7, 3, 4, 7, 4, 4, 8, 5, 4, 7, 6, 2, 7, 6, 5, 10, 5, 6, 7, 5, 7, 7, 6, 4, 10, 8, 3, 12, 6, 4, 11, 6, 5, 9, 7
Offset: 0

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Author

Ilya Gutkovskiy, Oct 25 2022

Keywords

Crossrefs

A357352 Number of partitions of n into distinct positive triangular numbers such that the number of parts is a triangular number.

Original entry on oeis.org

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

Views

Author

Ilya Gutkovskiy, Sep 25 2022

Keywords

Examples

			a(56) = 2 because we have [45,10,1] and [21,15,10,6,3,1].
		

Crossrefs

Programs

  • Maple
    b:= proc(n, i, t) option remember; (h-> `if`(n=0,
         `if`(issqr(8*t+1), 1, 0), `if`(n>i*(i+1)*(i+2)/6, 0,
         `if`(h>n, 0, b(n-h, i-1, t+1))+b(n, i-1, t))))(i*(i+1)/2)
        end:
    a:= n-> b(n, floor((sqrt(1+8*n)-1)/2), 0):
    seq(a(n), n=0..100);  # Alois P. Heinz, Sep 25 2022
  • Mathematica
    b[n_, i_, t_] := b[n, i, t] = With[{h = i(i+1)/2}, If[n == 0, If[IntegerQ@ Sqrt[8t+1], 1, 0], If[n > i(i+1)(i+2)/6, 0, If[h > n, 0, b[n-h, i-1, t+1]] + b[n, i-1, t]]]];
    a[n_] := b[n, Floor[(Sqrt[8n+1]-1)/2], 0];
    Table[a[n], {n, 0, 100}] (* Jean-François Alcover, Apr 22 2025, after Alois P. Heinz *)

A099200 Number of partitions of n into distinct odd triangular numbers.

Original entry on oeis.org

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

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Author

Reinhard Zumkeller, Oct 04 2004

Keywords

Examples

			a(70) = #{55+15, 45+21+3+1} = 2.
		

Crossrefs

A280423 G.f.: Product_{k>=1} (1 + x^(k*(k+1))) / (1 - x^k).

Original entry on oeis.org

1, 1, 3, 4, 7, 10, 17, 23, 36, 49, 71, 96, 136, 180, 248, 326, 437, 569, 752, 967, 1261, 1609, 2069, 2620, 3335, 4189, 5285, 6595, 8249, 10230, 12706, 15661, 19327, 23696, 29063, 35457, 43256, 52519, 63756, 77073, 93126, 112120, 134901, 161781, 193884, 231679
Offset: 0

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Author

Vaclav Kotesovec, Jan 02 2017

Keywords

Crossrefs

Programs

  • Mathematica
    nmax=60; CoefficientList[Series[Product[(1+x^(k*(k+1)))/(1-x^k), {k, 1, nmax}], {x, 0, nmax}], x]

Formula

a(n) ~ exp(sqrt(2*n/3)*Pi + 3^(1/4) * (sqrt(2)-1) * Zeta(3/2) * n^(1/4) / 2^(5/4) + 3*(2*sqrt(2)-3) * Zeta(3/2)^2 / (64*Pi)) / (8*sqrt(3)*n).

A281666 Expansion of Sum_{i>=1} x^(i*(i+1)/2)/(1 + x^(i*(i+1)/2)) * Product_{j>=1} (1 + x^(j*(j+1)/2)).

Original entry on oeis.org

1, 0, 1, 2, 0, 1, 2, 0, 2, 4, 2, 0, 2, 3, 1, 4, 3, 2, 6, 4, 3, 5, 0, 5, 9, 3, 2, 7, 6, 3, 11, 10, 0, 9, 12, 3, 11, 10, 8, 11, 8, 9, 9, 6, 12, 19, 15, 7, 15, 16, 4, 20, 21, 10, 23, 24, 10, 16, 19, 18, 20, 20, 17, 24, 27, 18, 28, 26, 19, 33, 30, 12, 33, 39, 25, 36, 38, 16, 32, 44, 29, 41, 48, 37, 41, 45, 33, 39, 44, 41
Offset: 1

Views

Author

Ilya Gutkovskiy, Jan 26 2017

Keywords

Comments

Total number of parts in all partitions of n into distinct nonzero triangular numbers (A000217).

Examples

			a(10) = 4 because we have [10], [6, 3, 1] and 1 + 3 = 4.
		

Crossrefs

Programs

  • Mathematica
    nmax = 90; Rest[CoefficientList[Series[Sum[x^(i (i + 1)/2)/(1 + x^(i (i + 1)/2)), {i, 1, nmax}] Product[1 + x^(j (j + 1)/2), {j, 1, nmax}], {x, 0, nmax}], x]]

Formula

G.f.: Sum_{i>=1} x^(i*(i+1)/2)/(1 + x^(i*(i+1)/2)) * Product_{j>=1} (1 + x^(j*(j+1)/2)).

A298850 Expansion of Product_{k>=1} (1 + x^(k*(k+1)/2))^(k*(k+1)/2).

Original entry on oeis.org

1, 1, 0, 3, 3, 0, 9, 9, 0, 19, 29, 10, 33, 63, 30, 66, 156, 90, 110, 300, 235, 276, 561, 465, 558, 1083, 1065, 1154, 1877, 1983, 2295, 3834, 3879, 3861, 6858, 7452, 7561, 12613, 13252, 13057, 22161, 25569, 24582, 35985, 44193, 44970, 63495, 79105, 77143, 104046, 134820, 138759, 182511, 222600
Offset: 0

Views

Author

Ilya Gutkovskiy, Mar 09 2018

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 53; CoefficientList[Series[Product[(1 + x^(k (k + 1)/2))^(k (k + 1)/2), {k, 1, nmax}], {x, 0, nmax}], x]

Formula

G.f.: Product_{k>=1} (1 + x^A000217(k))^A000217(k).

A300417 Expansion of Product_{k>=1} (1 + x^(k*(k+1)/2))^2.

Original entry on oeis.org

1, 2, 1, 2, 4, 2, 3, 6, 3, 4, 10, 8, 5, 10, 11, 8, 14, 16, 11, 18, 22, 18, 23, 22, 22, 34, 31, 26, 39, 40, 33, 50, 56, 36, 53, 74, 51, 62, 86, 68, 77, 98, 86, 88, 102, 106, 120, 130, 120, 136, 157, 134, 157, 194, 155, 182, 241, 194, 196, 256, 237, 236, 288, 282, 273, 324
Offset: 0

Views

Author

Ilya Gutkovskiy, Mar 05 2018

Keywords

Comments

Number of partitions of n into distinct triangular parts (A000217), with 2 types of each part.
Self-convolution of A024940.

Crossrefs

Programs

  • Mathematica
    nmax = 65; CoefficientList[Series[Product[(1 + x^(k (k + 1)/2))^2, {k, 1, nmax}], {x, 0, nmax}], x]

Formula

G.f.: Product_{k>=1} (1 + x^A000217(k))^2.
a(n) ~ exp(3*Pi^(1/3) * ((sqrt(2)-1) * Zeta(3/2)/2)^(2/3) * n^(1/3)) * ((sqrt(2)-1) * Zeta(3/2) / (2*Pi))^(1/3) / (4*sqrt(3) * n^(5/6)). - Vaclav Kotesovec, Mar 05 2018

A319256 Expansion of Product_{k>0} (1 + k*(k+1)/2 * x^(k*(k+1)/2)).

Original entry on oeis.org

1, 1, 0, 3, 3, 0, 6, 6, 0, 18, 28, 10, 0, 30, 30, 15, 75, 60, 45, 225, 180, 111, 111, 0, 333, 483, 150, 126, 604, 478, 378, 1572, 1194, 0, 3498, 3498, 351, 2115, 2044, 1333, 4833, 4620, 2946, 2526, 2100, 8043, 11133, 9810, 5175, 13773, 13638, 810, 31194, 34584, 6630
Offset: 0

Views

Author

Seiichi Manyama, Sep 15 2018

Keywords

Comments

Sum of products of terms in all partitions of n into distinct triangular numbers (A000217).

Examples

			a(16) = 75 because we have [15, 1], [10, 6], 15*1 = 15, 10*6 = 60 and 15 + 60 = 75.
		

Crossrefs

A329466 Expansion of Sum_{k>=1} (-1 + Product_{j>=1} (1 + x^(k*j*(j + 1)/2))).

Original entry on oeis.org

1, 1, 2, 2, 1, 3, 2, 2, 3, 3, 2, 4, 2, 3, 3, 4, 2, 5, 3, 5, 5, 4, 1, 6, 4, 3, 4, 7, 3, 7, 5, 7, 3, 5, 5, 8, 5, 6, 6, 8, 3, 10, 4, 7, 8, 7, 5, 10, 7, 10, 5, 10, 6, 9, 9, 13, 7, 8, 6, 14, 7, 10, 10, 14, 9, 12, 9, 12, 7, 17, 8, 14, 10, 14, 12, 17, 12, 12, 10, 20
Offset: 1

Views

Author

Ilya Gutkovskiy, Nov 13 2019

Keywords

Comments

Inverse Moebius transform of A024940.

Crossrefs

Programs

  • Mathematica
    nmax = 80; CoefficientList[Series[Sum[-1 + Product[(1 + x^(k j (j + 1)/2)), {j, 1, nmax}], {k, 1, nmax}], {x, 0, nmax}], x] // Rest

Formula

G.f.: Sum_{k>=1} A024940(k) * x^k / (1 - x^k).
a(n) = Sum_{d|n} A024940(d).
Previous Showing 31-40 of 42 results. Next