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.

Previous Showing 21-28 of 28 results.

A355164 a(n) = exp(-1/3) * Sum_{k>=0} (3*k + 2)^n / (3^k * k!).

Original entry on oeis.org

1, 3, 12, 63, 405, 3024, 25515, 239355, 2465478, 27600669, 333051669, 4303119330, 59202612693, 863285928327, 13288589222508, 215177742933579, 3654114236490393, 64902307993517160, 1202782377224829015, 23207417212751493327, 465302639045308247262, 9677171073270491712513, 208434297638273958963225
Offset: 0

Views

Author

Ilya Gutkovskiy, Jun 22 2022

Keywords

Crossrefs

Programs

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

Formula

E.g.f.: exp(2*x + (exp(3*x) - 1) / 3).
a(0) = 1; a(n) = 2 * a(n-1) + Sum_{k=1..n} binomial(n-1,k-1) * 3^(k-1) * a(n-k).
a(n) = Sum_{k=0..n} binomial(n,k) * 2^(n-k) * A004212(k).
a(n) ~ 3^(n + 2/3) * n^(n + 2/3) * exp(n/LambertW(3*n) - n - 1/3) / (sqrt(1 + LambertW(3*n)) * LambertW(3*n)^(n + 2/3)). - Vaclav Kotesovec, Jun 27 2022

A367744 Expansion of e.g.f. exp(1 - x - exp(3*x)).

Original entry on oeis.org

1, -4, 7, 17, -14, -637, -2951, 14126, 333205, 2076245, -12283700, -423234511, -4163106203, 8148184700, 952894223755, 15568620884189, 69314620864450, -2816256959131561, -83397946135434515, -1025683419252783946, 4726361848234575553, 525779836596438636689, 12363747028673287330948, 112888493670408785796989
Offset: 0

Views

Author

Ilya Gutkovskiy, Nov 29 2023

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 23; CoefficientList[Series[Exp[1 - x - Exp[3 x]], {x, 0, nmax}], x] Range[0, nmax]!
    a[0] = 1; a[n_] := a[n] = -a[n - 1] - Sum[Binomial[n - 1, k - 1] 3^k a[n - k], {k, 1, n}]; Table[a[n], {n, 0, 23}]
    Table[Sum[(-1)^(n - k) Binomial[n, k] 3^k BellB[k, -1], {k, 0, n}], {n, 0, 23}]

Formula

a(n) = exp(1) * Sum_{k>=0} (-1)^k * (3*k-1)^n / k!.
a(0) = 1; a(n) = -a(n-1) - Sum_{k=1..n} binomial(n-1,k-1) * 3^k * a(n-k).
a(n) = Sum_{k=0..n} (-1)^(n-k) * binomial(n,k) * 3^k * A000587(k).

A111673 Triangle, generated from A111579.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 5, 3, 1, 1, 1, 15, 11, 4, 1, 1, 1, 52, 49, 19, 5, 1, 1, 1, 203, 257, 109, 29, 6, 1, 1, 1, 877, 1539, 742, 201, 41, 7, 1, 1, 1, 4140, 10299, 5815, 1657, 331, 55, 8, 1, 1, 1, 21147, 75905, 51193, 15821, 3176, 505, 71, 9, 1, 1, 1, 115975, 609441, 498118, 170389, 35451, 5497, 729, 89, 10, 1, 1
Offset: 0

Views

Author

Gary W. Adamson, Aug 14 2005

Keywords

Comments

Columns are inverse binomial transforms of columns (k>0) of A111579.

Examples

			First few rows of the triangle are:
  1,
  1, 1,
  1, 1, 1,
  1, 2, 1, 1,
  1, 5, 3, 1, 1,
  1, 15, 11, 4, 1, 1,
  1, 52, 49, 19, 5, 1, 1,
  1, 203, 257, 109, 29, 6, 1, 1,
  1, 877, 1539, 742, 201, 41, 7, 1, 1,
  1, 4140, 10299, 5815, 1657, 331, 55, 8, 1, 1,
  ...
Inverse binomial transform of column 2 of A111579 (1, 2, 5, 15, 52, 203...) = column 2 (1, 1, 2, 5, 15, 52...).
		

Crossrefs

For two other versions of this triangle see A241578, A241579.

Extensions

More terms from N. J. A. Sloane, Apr 29 2014

A375174 Expansion of e.g.f. exp( (1/(1 - 9*x)^(1/3) - 1)/3 ).

Original entry on oeis.org

1, 1, 13, 289, 9073, 367681, 18249661, 1071805393, 72684954049, 5588943933313, 480445784729101, 45656401249018561, 4752397230972673393, 537724197016879848769, 65711109523289467682173, 8624825762253351871394161, 1210085772867351648907603201
Offset: 0

Views

Author

Seiichi Manyama, Aug 02 2024

Keywords

Crossrefs

Programs

  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(exp((1/(1-9*x)^(1/3)-1)/3)))

Formula

a(n) = Sum_{k=0..n} 9^(n-k) * |Stirling1(n,k)| * A004212(k) = 9^n * Sum_{k=0..n} (1/3)^k * |Stirling1(n,k)| * Bell_k(1/3), where Bell_n(x) is n-th Bell polynomial.
From Vaclav Kotesovec, Aug 02 2024: (Start)
a(n) = 36*(n-2)*a(n-1) - 18*(27*n^2 - 135*n + 172)*a(n-2) + (2916*n^3 - 26244*n^2 + 79056*n - 79703)*a(n-3) - 729*(n-4)*(n-3)*(3*n - 11)*(3*n - 10)*a(n-4).
a(n) ~ 3^(2*n - 1/4) * n^(n - 3/8) / (2*exp(n - 4*n^(1/4)/3^(3/2) + 1/3)) * (1 - 35/(32*sqrt(3)*n^(1/4))). (End)

A375176 Expansion of e.g.f. exp( (exp( (exp(9*x) - 1)/3 ) - 1)/3 ).

Original entry on oeis.org

1, 1, 13, 208, 4132, 99328, 2799073, 90310006, 3281661436, 132615087517, 5897867191525, 286140731152972, 15031839986716483, 849637058684740030, 51389339196926149645, 3310400979718767433801, 226189040323182011660827, 16333609964679285918346633
Offset: 0

Views

Author

Seiichi Manyama, Aug 02 2024

Keywords

Crossrefs

Programs

  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(exp((exp((exp(9*x)-1)/3)-1)/3)))

Formula

a(n) = Sum_{k=0..n} 9^(n-k) * Stirling2(n,k) * A004212(k) = 9^n * Sum_{k=0..n} (1/3)^k * Stirling2(n,k) * Bell_k(1/3), where Bell_n(x) is n-th Bell polynomial.

A369785 Expansion of e.g.f. exp( (exp(3*(exp(x)-1))-1)/3 ).

Original entry on oeis.org

1, 1, 5, 32, 252, 2368, 25865, 321310, 4461684, 68329293, 1142114917, 20663072796, 401891071075, 8355591197398, 184796601094141, 4329517995684305, 107060130166069859, 2785248872828731497, 76017344650249268158, 2171058618712177987046
Offset: 0

Views

Author

Seiichi Manyama, Feb 01 2024

Keywords

Crossrefs

Programs

  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(exp((exp(3*(exp(x)-1))-1)/3)))

Formula

a(n) = Sum_{k=0..n} Stirling2(n,k) * A004212(k).

A380259 Expansion of e.g.f. exp( (1/(1-2*x)^(3/2) - 1)/3 ).

Original entry on oeis.org

1, 1, 6, 51, 561, 7566, 120711, 2221311, 46269126, 1075249881, 27560477331, 771948530046, 23446574573841, 767288588019201, 26905482997736526, 1006166248423254171, 39962774633459923881, 1679677496419394133846, 74471142324541556576151
Offset: 0

Views

Author

Seiichi Manyama, Jan 18 2025

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Sum[3^k * 2^(n-k) * Abs[StirlingS1[n,k]] * BellB[k, 1/3], {k, 0, n}], {n, 0, 20}] (* Vaclav Kotesovec, Jan 23 2025 *)
  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(exp((1/(1-2*x)^(3/2)-1)/3)))

Formula

a(n) = Sum_{k=0..n} 2^(n-k) * |Stirling1(n,k)| * A004212(k) = Sum_{k=0..n} 3^k * 2^(n-k) * |Stirling1(n,k)| * Bell_k(1/3), where Bell_n(x) is n-th Bell polynomial.
a(n) = (1/exp(1/3)) * (-2)^n * n! * Sum_{k>=0} binomial(-3*k/2,n)/(3^k * k!).
a(n) ~ 2^(n + 3/10) * n^(n - 1/5) * exp(-1/3 + 2^(1/5)*n^(1/5)/4 + 5*2^(3/5)*n^(3/5)/6 - n) / sqrt(5) * (1 + 2^(4/5) / (30 * n^(1/5))). - Vaclav Kotesovec, Jan 23 2025

A380260 Expansion of e.g.f. exp( ((1+2*x)^(3/2) - 1)/3 ).

Original entry on oeis.org

1, 1, 2, 3, 9, 6, 111, -573, 7638, -95751, 1450431, -24643134, 468589617, -9843336567, 226448287794, -5662061186949, 152892006728841, -4434211761771978, 137468475061977663, -4536657554920874181, 158788359466681092966, -5875324355407515077439, 229142457698060305226367
Offset: 0

Views

Author

Seiichi Manyama, Jan 18 2025

Keywords

Crossrefs

Programs

  • Mathematica
    With[{nn=30},CoefficientList[Series[Exp[((1+2x)^(3/2)-1)/3],{x,0,nn}],x] Range[0,nn]!] (* Harvey P. Dale, Apr 29 2025 *)
  • PARI
    my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(((1+2*x)^(3/2)-1)/3)))

Formula

a(n) = Sum_{k=0..n} 2^(n-k) * Stirling1(n,k) * A004212(k) = Sum_{k=0..n} 3^k * 2^(n-k) * Stirling1(n,k) * Bell_k(1/3), where Bell_n(x) is n-th Bell polynomial.
a(n) = (1/exp(1/3)) * 2^n * n! * Sum_{k>=0} binomial(3*k/2,n)/(3^k * k!).
Previous Showing 21-28 of 28 results.