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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A238464 Generalized ordered Bell numbers Bo(7,n).

Original entry on oeis.org

1, 7, 105, 2359, 70665, 2646007, 118893705, 6232661239, 373405001865, 25167452766967, 1884759251911305, 155262005162499319, 13952854271421949065, 1358385484966283220727, 142418920493123648992905, 15998363870912950298468599
Offset: 0

Views

Author

Vincenzo Librandi, Mar 17 2014

Keywords

Comments

Row 7 of array A094416, which has more information.

Crossrefs

Programs

  • Magma
    m:=20; R:=LaurentSeriesRing(RationalField(), m); b:=Coefficients(R!(1/(8 - 7*Exp(x)))); [Factorial(n-1)*b[n]: n in [1..m]]; // Bruno Berselli, Mar 17 2014
    
  • Mathematica
    t=30; Range[0, t]! CoefficientList[Series[1/(8 - 7 Exp[x]), {x, 0, t}], x]
  • PARI
    x='x+O('x^66); Vec(serlaplace(1/(8 - 7*exp(x)))) \\ Joerg Arndt, Mar 17 2014

Formula

E.g.f.: 1/(8 - 7*exp(x)).
a(n) ~ n! / (8*(log(8/7))^(n+1)). - Vaclav Kotesovec, Mar 20 2014
a(0) = 1; a(n) = 7*a(n-1) - 8*Sum_{k=1..n-1} (-1)^k * binomial(n-1,k) * a(n-k). - Seiichi Manyama, Nov 17 2023

A344840 a(0) = 1; a(n) = 5 * Sum_{k=1..n} binomial(n,k) * a(k-1).

Original entry on oeis.org

1, 5, 35, 265, 2195, 19625, 187755, 1909185, 20521515, 232124745, 2752591475, 34108980105, 440444019835, 5912197332865, 82320781521195, 1186703083508025, 17680850448587155, 271845880552898985, 4307188044378111915, 70236616096770062945, 1177406236243423738475
Offset: 0

Views

Author

Ilya Gutkovskiy, Jun 07 2021

Keywords

Crossrefs

Programs

  • Mathematica
    a[0] = 1; a[n_] := a[n] = 5 Sum[Binomial[n, k] a[k - 1], {k, 1, n}]; Table[a[n], {n, 0, 20}]
    nmax = 20; A[] = 0; Do[A[x] = 1 + 5 x A[x/(1 - x)]/(1 - x)^2 + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]

Formula

G.f. A(x) satisfies: A(x) = 1 + 5 * x * A(x/(1 - x)) / (1 - x)^2.

A365588 Expansion of e.g.f. 1 / (1 + 5 * log(1-x)).

Original entry on oeis.org

1, 5, 55, 910, 20080, 553870, 18333050, 707959800, 31244562600, 1551289408800, 85579293493200, 5193226343508000, 343790892166398000, 24655487205067386000, 1904221630155352038000, 157574022827034258192000, 13908505761692419540320000
Offset: 0

Views

Author

Seiichi Manyama, Sep 10 2023

Keywords

Crossrefs

Column k=5 of A320079.
Cf. A094418.

Programs

  • Mathematica
    a[n_] := Sum[5^k * k! * Abs[StirlingS1[n, k]], {k, 0, n}]; Array[a, 17, 0] (* Amiram Eldar, Sep 13 2023 *)
  • PARI
    a(n) = sum(k=0, n, 5^k*k!*abs(stirling(n, k, 1)));

Formula

a(n) = Sum_{k=0..n} 5^k * k! * |Stirling1(n,k)|.
a(0) = 1; a(n) = 5 * Sum_{k=1..n} (k-1)! * binomial(n,k) * a(n-k).
a(n) ~ sqrt(2*Pi) * n^(n + 1/2) / (5 * exp(4*n/5) * (exp(1/5) - 1)^(n+1)). - Vaclav Kotesovec, Nov 11 2023

A344499 T(n, k) = F(n - k, k), where F(n, x) is the Fubini polynomial. Triangle read by rows, T(n, k) for 0 <= k <= n.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 0, 3, 2, 1, 0, 13, 10, 3, 1, 0, 75, 74, 21, 4, 1, 0, 541, 730, 219, 36, 5, 1, 0, 4683, 9002, 3045, 484, 55, 6, 1, 0, 47293, 133210, 52923, 8676, 905, 78, 7, 1, 0, 545835, 2299754, 1103781, 194404, 19855, 1518, 105, 8, 1, 0, 7087261, 45375130, 26857659, 5227236, 544505, 39390, 2359, 136, 9, 1
Offset: 0

Views

Author

Peter Luschny, May 21 2021

Keywords

Comments

The array rows are recursively generated by applying the Akiyama-Tanigawa algorithm to the powers (see the Python implementation below). In this way the array becomes the image of A004248 under the AT-transformation when applied to the columns of A004248. This makes the array closely linked to A371761, which is generated in the same way, but applied to the rows of A004248. - Peter Luschny, Apr 27 2024

Examples

			Triangle starts:
[0] 1;
[1] 0, 1;
[2] 0, 1,      1;
[3] 0, 3,      2,       1;
[4] 0, 13,     10,      3,       1;
[5] 0, 75,     74,      21,      4,      1;
[6] 0, 541,    730,     219,     36,     5,     1;
[7] 0, 4683,   9002,    3045,    484,    55,    6,    1;
[8] 0, 47293,  133210,  52923,   8676,   905,   78,   7,   1;
[9] 0, 545835, 2299754, 1103781, 194404, 19855, 1518, 105, 8, 1;
.
Seen as an array A(n, k) = T(n + k, n):
[0] [1, 0,   0,    0,     0,       0,         0, ...  A000007
[1] [1, 1,   3,   13,    75,     541,      4683, ...  A000670
[2] [1, 2,  10,   74,   730,    9002,    133210, ...  A004123
[3] [1, 3,  21,  219,  3045,   52923,   1103781, ...  A032033
[4] [1, 4,  36,  484,  8676,  194404,   5227236, ...  A094417
[5] [1, 5,  55,  905, 19855,  544505,  17919055, ...  A094418
[6] [1, 6,  78, 1518, 39390, 1277646,  49729758, ...  A094419
[7] [1, 7, 105, 2359, 70665, 2646007, 118893705, ...  A238464
		

Crossrefs

Variant of the array is A094416 (which has column 0 and row 0 missing).
The coefficients of the Fubini polynomials are A131689.
Cf. A094420 (main diagonal of array), A372346 (row sums), A004248, A371761.

Programs

  • Maple
    F := proc(n) option remember; if n = 0 then return 1 fi:
    expand(add(binomial(n, k)*F(n - k)*x, k = 1..n)) end:
    seq(seq(subs(x = k, F(n - k)), k = 0..n), n = 0..10);
  • Mathematica
    F[n_] := F[n] = If[n == 0, 1,
       Expand[Sum[Binomial[n, k]*F[n - k]*x, {k, 1, n}]]];
    Table[Table[F[n - k] /. x -> k, {k, 0, n}], {n, 0, 10}] // Flatten (* Jean-François Alcover, Jun 06 2024, after Peter Luschny *)
  • SageMath
    # Computes the triangle.
    @cached_function
    def F(n):
        R. = PolynomialRing(ZZ)
        if n == 0: return R(1)
        return R(sum(binomial(n, k)*F(n - k)*x for k in (1..n)))
    def Fval(n): return [F(n - k).substitute(x = k) for k in (0..n)]
    for n in range(10): print(Fval(n))
    
  • SageMath
    # Computes the square array using the Akiyama-Tanigawa algorithm.
    def ATFubini(n, len):
        A = [0] * len
        R = [0] * len
        for k in range(len):
            R[k] = (n + 1)**k  # Chancing this to R[k] = k**n generates A371761.
            for j in range(k, 0, -1):
                R[j - 1] = j * (R[j] - R[j - 1])
            A[k] = R[0]
        return A
    for n in range(8): print([n], ATFubini(n, 7))  # Peter Luschny, Apr 27 2024

Formula

T(n, k) = (n - k)! * [x^(n - k)] (1 / (1 + k * (1 - exp(x)))).
T(2*n, n) = A094420(n).

A365568 Expansion of e.g.f. 1 / (6 - 5 * exp(x))^(2/5).

Original entry on oeis.org

1, 2, 16, 212, 3964, 95804, 2840140, 99760124, 4050900268, 186700658972, 9628444876108, 549349531209404, 34355463031007596, 2336935606239856988, 171779270567736231052, 13568895740353218626300, 1146225546710339427328684, 103113032296428007394503580
Offset: 0

Views

Author

Seiichi Manyama, Sep 09 2023

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := Sum[Product[5*j + 2, {j, 0, k - 1}] * StirlingS2[n, k], {k, 0, n}]; Array[a, 18, 0] (* Amiram Eldar, Sep 11 2023 *)
  • PARI
    a(n) = sum(k=0, n, prod(j=0, k-1, 5*j+2)*stirling(n, k, 2));

Formula

a(n) = Sum_{k=0..n} (Product_{j=0..k-1} (5*j+2)) * Stirling2(n,k).
a(0) = 1; a(n) = Sum_{k=1..n} (5 - 3*k/n) * binomial(n,k) * a(n-k).
a(n) ~ sqrt(Pi) * 2^(1/10) * n^(n - 1/10) / (3^(2/5) * Gamma(2/5) * exp(n) * log(6/5)^(n + 2/5)). - Vaclav Kotesovec, Nov 11 2023
a(0) = 1; a(n) = 2*a(n-1) - 6*Sum_{k=1..n-1} (-1)^k * binomial(n-1,k) * a(n-k). - Seiichi Manyama, Nov 16 2023

A365569 Expansion of e.g.f. 1 / (6 - 5 * exp(x))^(3/5).

Original entry on oeis.org

1, 3, 27, 387, 7659, 193491, 5948091, 215446563, 8984708235, 423944899443, 22328393101659, 1298429924941251, 82625791930962219, 5711012035686681363, 426058604580805219323, 34121803137713388036963, 2919847869159667841599947, 265868538017899566748612275
Offset: 0

Views

Author

Seiichi Manyama, Sep 09 2023

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := Sum[Product[5*j + 3, {j, 0, k - 1}] * StirlingS2[n, k], {k, 0, n}]; Array[a, 18, 0] (* Amiram Eldar, Sep 11 2023 *)
    With[{nn=20},CoefficientList[Series[1/(6-5*Exp[x])^(3/5),{x,0,nn}],x] Range[0,nn]!] (* Harvey P. Dale, Nov 03 2024 *)
  • PARI
    a(n) = sum(k=0, n, prod(j=0, k-1, 5*j+3)*stirling(n, k, 2));

Formula

a(n) = Sum_{k=0..n} (Product_{j=0..k-1} (5*j+3)) * Stirling2(n,k).
a(0) = 1; a(n) = Sum_{k=1..n} (5 - 2*k/n) * binomial(n,k) * a(n-k).
a(n) ~ sqrt(2*Pi) * n^(n + 1/10) / (6^(3/5) * Gamma(3/5) * exp(n) * log(6/5)^(n + 3/5)). - Vaclav Kotesovec, Nov 11 2023
a(0) = 1; a(n) = 3*a(n-1) - 6*Sum_{k=1..n-1} (-1)^k * binomial(n-1,k) * a(n-k). - Seiichi Manyama, Nov 16 2023

A365570 Expansion of e.g.f. 1 / (6 - 5 * exp(x))^(4/5).

Original entry on oeis.org

1, 4, 40, 616, 12856, 338728, 10781176, 402250216, 17213590840, 831013114792, 44675458306168, 2646758624166760, 171319908334752184, 12028779733435667752, 910538645035885918456, 73918475291961325824232, 6406179168820339231897144
Offset: 0

Views

Author

Seiichi Manyama, Sep 09 2023

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := Sum[Product[5*j + 4, {j, 0, k - 1}] * StirlingS2[n, k], {k, 0, n}]; Array[a, 17, 0] (* Amiram Eldar, Sep 11 2023 *)
  • PARI
    a(n) = sum(k=0, n, prod(j=0, k-1, 5*j+4)*stirling(n, k, 2));

Formula

a(n) = Sum_{k=0..n} (Product_{j=0..k-1} (5*j+4)) * Stirling2(n,k).
a(0) = 1; a(n) = Sum_{k=1..n} (5 - k/n) * binomial(n,k) * a(n-k).
a(n) ~ sqrt(2*Pi) * n^(n + 3/10) / (6^(4/5) * Gamma(4/5) * exp(n) * log(6/5)^(n + 4/5)). - Vaclav Kotesovec, Nov 11 2023
a(0) = 1; a(n) = 4*a(n-1) - 6*Sum_{k=1..n-1} (-1)^k * binomial(n-1,k) * a(n-k). - Seiichi Manyama, Nov 16 2023

A238465 Generalized ordered Bell numbers Bo(8,n).

Original entry on oeis.org

1, 8, 136, 3464, 117640, 4993928, 254396296, 15119104904, 1026912225160, 78468091562888, 6662087721342856, 622186077361470344, 63389713864392140680, 6996476832548305415048, 831619554631233264449416, 105909083171031626820475784
Offset: 0

Views

Author

Vincenzo Librandi, Mar 18 2014

Keywords

Comments

Row 8 of array A094416, which has more information.

Crossrefs

Programs

  • Magma
    m:=20; R:=LaurentSeriesRing(RationalField(), m); b:=Coefficients(R!(1/(9 - 8*Exp(x)))); [Factorial(n-1)*b[n]: n in [1..m]];
  • Mathematica
    t = 30; Range[0, t]! CoefficientList[Series[1/(9 - 8 Exp[x]), {x, 0, t}], x]

Formula

E.g.f.: 1/(9 - 8*exp(x)).
a(n) ~ n! / (9*(log(9/8))^(n+1)). - Vaclav Kotesovec, Mar 20 2014
a(0) = 1; a(n) = 8*a(n-1) - 9*Sum_{k=1..n-1} (-1)^k * binomial(n-1,k) * a(n-k). - Seiichi Manyama, Nov 17 2023

A355113 Expansion of e.g.f. 5 / (6 - 5*x - exp(5*x)).

Original entry on oeis.org

1, 2, 13, 133, 1779, 29565, 589705, 13728695, 365295695, 10934634985, 363678872325, 13305294463275, 531030788556475, 22960273845453725, 1069101897816615425, 53336480697298243375, 2838300249311563302375, 160480124820425410172625, 9607441647405962075600125
Offset: 0

Views

Author

Ilya Gutkovskiy, Jun 19 2022

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 18; CoefficientList[Series[5/(6 - 5 x - Exp[5 x]), {x, 0, nmax}], x] Range[0, nmax]!
    a[0] = 1; a[n_] := a[n] = n a[n - 1] + Sum[Binomial[n, k] 5^(k - 1) a[n - k], {k, 1, n}]; Table[a[n], {n, 0, 18}]

Formula

a(0) = 1; a(n) = n * a(n-1) + Sum_{k=1..n} binomial(n,k) * 5^(k-1) * a(n-k).
a(n) ~ n! / ((1 + LambertW(exp(6))) * ((6 - LambertW(exp(6)))/5)^(n+1)). - Vaclav Kotesovec, Jun 19 2022

A365604 Expansion of e.g.f. 1 / (1 - 5 * log(1 + x)).

Original entry on oeis.org

1, 5, 45, 610, 11020, 248870, 6744350, 213233400, 7704814200, 313199930400, 14146162064400, 702826758144000, 38093116667766000, 2236695336601458000, 141433354184701746000, 9582086196220281456000, 692463727252196674560000
Offset: 0

Views

Author

Seiichi Manyama, Sep 11 2023

Keywords

Crossrefs

Column k=5 of A320080.

Programs

  • Mathematica
    a[n_] := Sum[5^k * k! * StirlingS1[n, k], {k, 0, n}]; Array[a, 17, 0] (* Amiram Eldar, Sep 13 2023 *)
    With[{nn=20},CoefficientList[Series[1/(1-5*Log[1+x]),{x,0,nn}],x] Range[0,nn]!] (* Harvey P. Dale, Aug 05 2025 *)
  • PARI
    a(n) = sum(k=0, n, 5^k*k!*stirling(n, k, 1));

Formula

a(n) = Sum_{k=0..n} 5^k * k! * Stirling1(n,k).
a(0) = 1; a(n) = 5 * Sum_{k=1..n} (-1)^(k-1) * (k-1)! * binomial(n,k) * a(n-k).
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