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 1-10 of 11 results. Next

A061698 Erroneous version of A061684.

Original entry on oeis.org

1, 1, 5, 64, 1613, 69026, 4566992, 437665649, 57903766800
Offset: 0

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Author

Keywords

A091315 Number of orbits of length n under the map whose periodic points are counted by A061684.

Original entry on oeis.org

1, 2, 21, 402, 13805, 761154, 62523664, 7237970648, 1132600004910, 231900134422880, 60528794385067778, 19713593779259862624, 7869483395065035685162, 3792402572391137423764584
Offset: 1

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Author

Thomas Ward, Feb 24 2004

Keywords

Comments

Old name was: A061684 appears to count the periodic points for a certain map. If so, then this is the sequence of the numbers of orbits of length n.

Examples

			The sequence A061684 begins 1,1,5,64,1613, so a(3)=(b(3)-b(1))/3=21.
		

Crossrefs

Cf. A061684.

Formula

If b(n) is the (n+1)th term in A061684, then a(n) = (1/n)*Sum_{d|n}mu(d)b(n/d).

Extensions

Name clarified by Michel Marcus, May 14 2015

A275043 Number A(n,k) of set partitions of [k*n] such that within each block the numbers of elements from all residue classes modulo k are equal for k>0, A(n,0)=1; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 3, 5, 1, 1, 1, 5, 16, 15, 1, 1, 1, 9, 64, 131, 52, 1, 1, 1, 17, 298, 1613, 1496, 203, 1, 1, 1, 33, 1540, 25097, 69026, 22482, 877, 1, 1, 1, 65, 8506, 461105, 4383626, 4566992, 426833, 4140, 1, 1, 1, 129, 48844, 9483041, 350813126, 1394519922, 437665649, 9934563, 21147, 1
Offset: 0

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Author

Alois P. Heinz, Jul 14 2016

Keywords

Examples

			A(2,2) = 3: 1234, 12|34, 14|23.
A(2,3) = 5: 123456, 123|456, 126|345, 135|246, 156|234.
A(2,4) = 9: 12345678, 1234|5678, 1238|4567, 1247|3568, 1278|3456, 1346|2578, 1368|2457, 1467|2358, 1678|2345.
A(3,2) = 16: 123456, 1234|56, 1236|45, 1245|36, 1256|34, 12|3456, 12|34|56, 12|36|45, 1346|25, 1456|23, 14|2356, 14|23|56, 16|2345, 16|23|45, 14|25|36, 16|25|34.
Square array A(n,k) begins:
  1,   1,     1,       1,          1,            1,               1, ...
  1,   1,     1,       1,          1,            1,               1, ...
  1,   2,     3,       5,          9,           17,              33, ...
  1,   5,    16,      64,        298,         1540,            8506, ...
  1,  15,   131,    1613,      25097,       461105,         9483041, ...
  1,  52,  1496,   69026,    4383626,    350813126,     33056715626, ...
  1, 203, 22482, 4566992, 1394519922, 573843627152, 293327384637282, ...
		

Crossrefs

Rows n=0+1,2-5 give: A000012, A094373, A275100, A275101, A275102.
Main diagonal gives A275044.
Cf. A345400.

Programs

  • Maple
    A:= proc(n, k) option remember; `if`(k*n=0, 1, add(
           binomial(n, j)^k*(n-j)*A(j, k), j=0..n-1)/n)
        end:
    seq(seq(A(n, d-n), n=0..d), d=0..12);
  • Mathematica
    A[n_, k_] := A[n, k] = If[k*n == 0, 1, Sum[Binomial[n, j]^k*(n-j)*A[j, k], {j, 0, n-1}]/n]; Table[A[n, d-n], {d, 0, 12}, {n, 0, d}] // Flatten (* Jean-François Alcover, Jan 17 2017, translated from Maple *)

A061692 Triangle of generalized Stirling numbers.

Original entry on oeis.org

1, 1, 4, 1, 27, 36, 1, 172, 864, 576, 1, 1125, 17500, 36000, 14400, 1, 7591, 351000, 1746000, 1944000, 518400, 1, 52479, 7197169, 80262000, 191394000, 133358400, 25401600, 1, 369580, 151633440, 3691514176, 17188416000, 23866214400, 11379916800, 1625702400
Offset: 1

Views

Author

N. J. A. Sloane, Jun 19 2001

Keywords

Examples

			1; 1,4; 1,27,36; 1,172,864,576; ...
		

Crossrefs

Diagonals give A001044, A061695, A061693, A061694. Cf. A061691.
Row sums give A061684.

Programs

  • Maple
    b:= proc(n) option remember; expand(
          `if`(n=0, 1, add(x*b(n-i)/i!^3, i=1..n)))
        end:
    T:= n-> (p-> seq(coeff(p, x, i)/i!, i=1..n))(b(n)*n!^3):
    seq(T(n), n=1..10);  # Alois P. Heinz, Sep 10 2019
  • Mathematica
    R[0, ] = 1; R[n, x_] := R[n, x] = x*Sum[Binomial[n, k]^2*Binomial[n-1, k]*R[k, x], {k, 0, n-1}]; Table[CoefficientList[R[n, x], x] // Rest, {n, 1, 8}] // Flatten (* Jean-François Alcover, Sep 01 2015, after Peter Bala *)

Formula

T(n, k) = 1/k!*Sum multinomial(n, n_1, n_2, ..n_k)^3, where the sum extends over all compositions (n_1, n_2, .., n_k) of n into exactly k nonnegative parts. - Vladeta Jovovic, Apr 23 2003
The row polynomials R(n,x) satisfy the recurrence equation R(n,x) = x*( sum {k = 0..n-1} binomial(n,k)^2*binomial(n-1,k)*R(k,x) ) with R(0,x) = 1. Also R(n,x + y) = sum {k = 0..n} binomial(n,k)^3*R(k,x)*R(n-k,y). - Peter Bala, Sep 17 2013

Extensions

More terms from Vladeta Jovovic, Apr 23 2003

A342197 a(0) = 1; a(n) = Sum_{k=1..n} binomial(n,k)^3 * a(k-1).

Original entry on oeis.org

1, 1, 9, 63, 919, 18919, 505639, 18602319, 877402487, 51212704151, 3688010412503, 321523601578079, 33283248550719793, 4050897039400696253, 574469890816237292037, 93943844587040615104177, 17565329004174205621822169, 3730161837629377369026433019
Offset: 0

Views

Author

Ilya Gutkovskiy, Mar 04 2021

Keywords

Crossrefs

Programs

  • Mathematica
    a[0] = 1; a[n_] := a[n] = Sum[Binomial[n, k]^3 a[k - 1], {k, 1, n}]; Table[a[n], {n, 0, 17}]

A336210 a(0) = 1; a(n) = -(1/n) * Sum_{k=0..n-1} binomial(n,k)^3 * (n-k) * a(k).

Original entry on oeis.org

1, -1, 3, -10, -117, 5224, -23010, -10319891, 463834315, 69461529092, -10005601418172, -1323175060249241, 468450359815048182, 63281374513705043227, -46495538420749056681263, -7147072328212024308730535, 9119277358213513566069911755, 1827085356172328516064256064092
Offset: 0

Views

Author

Ilya Gutkovskiy, Jul 12 2020

Keywords

Crossrefs

Programs

  • Mathematica
    a[0] = 1; a[n_] := a[n] = -(1/n) Sum[Binomial[n, k]^3 (n - k) a[k], {k, 0, n - 1}]; Table[a[n], {n, 0, 17}]
    nmax = 17; CoefficientList[Series[Exp[-Sum[x^k/(k!)^3, {k, 1, nmax}]], {x, 0, nmax}], x] Range[0, nmax]!^3

Formula

a(n) = (n!)^3 * [x^n] exp(-Sum_{k>=1} x^k / (k!)^3).

A352466 a(0) = 1; a(n) = (1/n) * Sum_{k=1..n} binomial(2*n,2*k)^3 * k * a(n-k).

Original entry on oeis.org

1, 1, 109, 124876, 704029453, 13294133177626, 665514245564815384, 75462508236267111825685, 17305487139219914670764064013, 7368678746697280907127091048286734, 5449131877967324738667220718996986592734, 6632563741264033978048120096103173533343094035
Offset: 0

Views

Author

Ilya Gutkovskiy, Mar 17 2022

Keywords

Crossrefs

Programs

  • Mathematica
    a[0] = 1; a[n_] := a[n] = (1/n) Sum[Binomial[2 n, 2 k]^3 k a[n - k], {k, 1, n}]; Table[a[n], {n, 0, 11}]
    nmax = 22; Take[CoefficientList[Series[Exp[Sum[x^(2 k)/(2 k)!^3, {k, 1, nmax}]], {x, 0, nmax}], x] Range[0, nmax]!^3, {1, -1, 2}]

Formula

Sum_{n>=0} a(n) * x^(2*n) / (2*n)!^3 = exp( Sum_{n>=1} x^(2*n) / (2*n)!^3 ).

A061699 Generalized Bell numbers.

Original entry on oeis.org

1, 0, 1, 1, 109, 1001, 128876, 4682637, 792013069, 75022864345, 17347941915130, 3306782335589129, 1063995670771466456, 344173484059603653963, 153912612667103172679837, 75571251960991348967876564, 46271172080109731069460430093, 32072712892330804080630204907257
Offset: 0

Views

Author

N. J. A. Sloane, Jun 19 2001

Keywords

Crossrefs

Formula

Sum_{n>=0} a(n) * x^n / (n!)^3 = exp(Sum_{n>=2} x^n / (n!)^3). - Ilya Gutkovskiy, Jul 12 2020

Extensions

More terms from Ilya Gutkovskiy, Jul 12 2020

A061700 Generalized Bell numbers.

Original entry on oeis.org

1, 0, 0, 1, 1, 1, 4001, 42876, 347117, 792865081, 37062990505, 1164982989754, 2135094241854476, 289654511654619255, 24938050464296749001, 41388115708273073076689, 12793631315199589229518093, 2452257460931091883072686073, 3961922987460317585057396895353
Offset: 0

Views

Author

N. J. A. Sloane, Jun 19 2001

Keywords

Crossrefs

Formula

Sum_{n>=0} a(n) * x^n / (n!)^3 = exp(Sum_{n>=3} x^n / (n!)^3). - Ilya Gutkovskiy, Jul 12 2020

Extensions

More terms from Ilya Gutkovskiy, Jul 12 2020

A346185 a(0) = 1; a(n) = Sum_{k=0..n-1} binomial(n-1,k)^3 * a(k).

Original entry on oeis.org

1, 1, 2, 11, 93, 1294, 26045, 714391, 26109426, 1224739755, 71807248783, 5173027197636, 450173748220033, 46617339568635115, 5677430539873463470, 804907754967314483801, 131598260940217897338131, 24609634809861999705338820, 5226508081059269450476666513
Offset: 0

Views

Author

Ilya Gutkovskiy, Jul 09 2021

Keywords

Crossrefs

Programs

  • Mathematica
    a[0] = 1; a[n_] := a[n] = Sum[Binomial[n - 1, k]^3 a[k], {k, 0, n - 1}]; Table[a[n], {n, 0, 18}]
Showing 1-10 of 11 results. Next