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 11-20 of 23 results. Next

A089258 Transposed version of A080955: T(n,k) = A080955(k,n), n>=0, k>=-1.

Original entry on oeis.org

1, 1, 0, 1, 1, 1, 1, 2, 2, 2, 1, 3, 5, 6, 9, 1, 4, 10, 16, 24, 44, 1, 5, 17, 38, 65, 120, 265, 1, 6, 26, 78, 168, 326, 720, 1854, 1, 7, 37, 142, 393, 872, 1957, 5040, 14833, 1, 8, 50, 236, 824, 2208, 5296, 13700, 40320, 133496, 1, 9, 65, 366, 1569, 5144, 13977, 37200, 109601, 362880, 1334961
Offset: 0

Views

Author

Philippe Deléham, Dec 12 2003

Keywords

Comments

Can be extended to columns with negative indices k<0 via T(n,k) = A292977(n,-k). - Max Alekseyev, Mar 06 2018

Examples

			n\k -1   0   1    2    3    4     5     6  ...
----------------------------------------------
0  | 1,  1,  1,   1,   1,   1,    1,    1, ...
1  | 0,  1,  2,   3,   4,   5,    6,    7, ...
2  | 1,  2,  5,  10,  17,  26,   37,   50, ...
3  | 2,  6, 16,  38,  78, 152,  236,  366, ...
4  | 9, 24, 65, 168, 393, 824, 1569, 2760, ...
...
		

Crossrefs

Main diagonal gives A217701.

Programs

  • Mathematica
    (* Assuming offset (0, 0): *)
    T[n_, k_] := Exp[k - 1] Gamma[n + 1, k - 1];
    Table[T[k, n - k], {n, 0, 10}, {k, 0, n}] // Flatten  (* Peter Luschny, Dec 24 2021 *)

Formula

For n > 0, k >= -1, T(n,k) is the permanent of the n X n matrix with k+1 on the diagonal and 1 elsewhere.
T(0,k) = 1.
T(n,k) = Sum_{j>=0} A008290(n,j) * (k+1)^j.
T(n,k) = n*T(n-1, k) + k^n .
T(n,k) = n! * Sum_{j=0..n} k^j/j!.
E.g.f. for k-th column: exp(k*x)/(1-x).
Assuming n >= 0, k >= 0: T(n, k) = exp(k-1)*Gamma(n+1, k-1). - Peter Luschny, Dec 24 2021

Extensions

Edited and changed offset for k to -1 by Max Alekseyev, Mar 08 2018

A263823 a(n) = n!*Sum_{k=0..n} Fibonacci(k-1)/k!, where Fibonacci(-1) = 1, Fibonacci(n) = A000045(n) for n>=0.

Original entry on oeis.org

1, 1, 3, 10, 42, 213, 1283, 8989, 71925, 647346, 6473494, 71208489, 854501957, 11108525585, 155519358423, 2332790376722, 37324646028162, 634518982479741, 11421341684636935, 217005492008104349, 4340109840162091161, 91142306643403921146, 2005130746154886276158
Offset: 0

Views

Author

Vladimir Reshetnikov, Oct 27 2015

Keywords

Examples

			For n = 3, a(3) = 3!*(Fibonacci(-1)/0! + Fibonacci(0)/1! + Fibonacci(1)/2! + Fibonacci(2)/3!) = 6*(1 + 0 + 1/2 + 1/6) = 10.
For n = 5, Gamma(5+1, phi)*exp(phi) = 120*sqrt(5) + 333 = 240*phi + 213, so a(5) = 213.
G.f. = 1 + x + 3*x^2 + 10*x^3 + 42*x^4 + 213*x^5 + 1283*x^6 + 8989*x^7 + 71925*x^8 + ...
		

Crossrefs

Cf. A009102, A009551, A000142, A000166, A000522, A000023, A053486, A010844 (incomplete Gamma function values at other points).

Programs

  • Mathematica
    Table[n! Sum[Fibonacci[k-1]/k!, {k, 0, n}], {n, 0, 22}]
    Round@Table[(E^(1-GoldenRatio) GoldenRatio Gamma[n+1, 1-GoldenRatio] + E^GoldenRatio Gamma[n+1, GoldenRatio]/GoldenRatio)/Sqrt[5], {n, 0, 22}]

Formula

a(n) = (Gamma(n+1, 1-phi)*exp(1-phi)*phi+Gamma(n+1, phi)*exp(phi)/phi)/sqrt(5), where Gamma(a, x) is the upper incomplete Gamma function, phi=(1+sqrt(5))/2.
a(n) = (phi^(n-1)*hypergeom([1,-n], [], 1-phi)-(-phi)^(1-n)*hypergeom([1,-n], [], phi))/sqrt(5).
Gamma(n+1, phi)*exp(phi) = A111139(n)*phi + a(n).
E.g.f.: (exp(phi*x)/phi+exp(-x/phi)*phi)/(sqrt(5)*(1-x)) = exp(x/2)*(cosh(x*sqrt(5)/2)-sinh(x*sqrt(5)/2)/sqrt(5))/(1-x).
Recurrence: a(0) = 1, a(1) = 1, a(2) = 3, a(n) = (n+1)*a(n-1)+(2-n)*a(n-2)+(2-n)*a(n-3).
a(n) ~ 2*exp(phi-n)*n^(n+1/2)*(1+exp(-sqrt(5))*phi^2)*sqrt(Pi/10)/phi.
0 = a(n)*(+a(n+1) + a(n+2) - 4*a(n+3) + a(n+4)) + a(n+1)*(+a(n+1) + 3*a(n+2) - 5*a(n+3) + a(n+4)) + a(n+2)*(+2*a(n+2) - a(n+4)) + a(n+3)*(+a(n+3)) if n>=0. - Michael Somos, Oct 30 2015

A327997 Triangle read by rows: coefficients of the polynomials given by KummerU(-n, 1 - n - x, 3).

Original entry on oeis.org

1, 3, 1, 9, 7, 1, 27, 38, 12, 1, 81, 192, 101, 18, 1, 243, 969, 755, 215, 25, 1, 729, 5115, 5494, 2205, 400, 33, 1, 2187, 29322, 40971, 21469, 5355, 679, 42, 1, 6561, 187992, 323658, 209356, 66619, 11452, 1078, 52, 1, 19683, 1370745, 2764926, 2111318, 813645, 176295, 22302, 1626, 63, 1
Offset: 0

Views

Author

Peter Luschny, Oct 27 2019

Keywords

Comments

KummerU(-n, 1-n-x, 1) are the Charlier polynomials with coefficients in A094816, the coefficients of KummerU(-n, 1-n-x, 2) are in |A137346|.
The exponential generating function of this family of sequences of polynomials is in its general form (1-t)^(-x)*exp(alpha*t) with a parameter alpha.

Examples

			The triangle starts:
      1;
      3,       1;
      9,       7,       1;
     27,      38,      12,       1;
     81,     192,     101,      18,      1;
    243,     969,     755,     215,     25,      1;
    729,    5115,    5494,    2205,    400,     33,     1;
   2187,   29322,   40971,   21469,   5355,    679,    42,    1;
   6561,  187992,  323658,  209356,  66619,  11452,  1078,   52,  1;
  19683, 1370745, 2764926, 2111318, 813645, 176295, 22302, 1626, 63, 1;
		

Crossrefs

A094816 (z=1), |A137346| (z=2), this sequence (z=3).
Columns k=0..3 give A000244, A346395, A381052, A382701.
Row sums in A053486.

Programs

  • Maple
    egf := exp(3*t)*(1-t)^(-x): ser := series(egf, t, 12): p := n -> coeff(ser, t, n):
    seq(print(n!*seq(coeff(p(n), x, k), k=0..n)), n=0..9);
  • Mathematica
    p [n_] := HypergeometricU[-n, 1 - n - x, 3];
    Table[CoefficientList[p[n], x], {n, 0, 9}] // Flatten
  • PARI
    T(n, k) = sum(j=k, n, 3^(n-j)*binomial(n, j)*abs(stirling(j, k, 1))); \\ Seiichi Manyama, Apr 19 2025

Formula

T(n, k) = n!*[x^k] p(n) where p(n) = [t^n] exp(3*t)*(1-t)^(-x).
From Igor Victorovich Statsenko, Feb 14 2025: (Start)
T(m, n, k) = Sum_{i=0..n} Stirling1(n-i, k)*binomial(n, i)*m^(i)*(-1)^(n-k), for m = -3.
The triangle T(n,k) is a representative of the parametric family of triangles T(m,n,k), whose columns are the coefficients of the standard expansion of the function f(x) = (-log(1-x))^(k)*exp(-m*x)/k! for the case m=-3. (End)

A346395 Expansion of e.g.f. -log(1 - x) * exp(3*x).

Original entry on oeis.org

0, 1, 7, 38, 192, 969, 5115, 29322, 187992, 1370745, 11392839, 107043606, 1122823944, 12989320785, 164040593067, 2243143392138, 32994768719376, 519229765892241, 8701862242296807, 154700700117472422, 2907409255935736752, 57588370882960384377, 1198954118077558162875
Offset: 0

Views

Author

Ilya Gutkovskiy, Jul 15 2021

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 22; CoefficientList[Series[-Log[1 - x] Exp[3 x], {x, 0, nmax}], x] Range[0, nmax]!
    Table[n! Sum[3^k/((n - k) k!), {k, 0, n - 1}], {n, 0, 22}]
  • PARI
    a_vector(n) = my(v=vector(n+1, i, if(i==2, 1, 0))); for(i=2, n, v[i+1]=(i+2)*v[i]-3*(i-1)*v[i-1]+3^(i-1)); v; \\ Seiichi Manyama, May 27 2022

Formula

a(n) = n! * Sum_{k=0..n-1} 3^k / ((n-k) * k!).
a(n) ~ exp(3) * (n-1)!. - Vaclav Kotesovec, Aug 09 2021
a(0) = 0, a(1) = 1, a(n) = (n+2) * a(n-1) - 3 * (n-1) * a(n-2) + 3^(n-1). - Seiichi Manyama, May 27 2022

A217629 Triangle, read by rows, where T(n,k) = k!*C(n, k)*3^(n-k) for n>=0, k=0..n.

Original entry on oeis.org

1, 3, 1, 9, 6, 2, 27, 27, 18, 6, 81, 108, 108, 72, 24, 243, 405, 540, 540, 360, 120, 729, 1458, 2430, 3240, 3240, 2160, 720, 2187, 5103, 10206, 17010, 22680, 22680, 15120, 5040, 6561, 17496, 40824, 81648, 136080, 181440, 181440, 120960, 40320
Offset: 0

Views

Author

Vincenzo Librandi, Nov 10 2012

Keywords

Comments

Triangle formed by the derivatives of x^n evaluated at x=3.
Sum(T(n,k), k=0..n) = A053486(n) (see the Formula section of A053486). Also:
first column: A000244;
second column: A027471;
third column: 2*A027472;
fourth column: 6*A036216;
fifth column: 24*A036217.

Examples

			Triangle begins:
1;
3,     1;
9,     6,     2;
27,    27,    18,     6;
81,    108,   108,    72,     24;
243,   405,   540,    540,    360,    120;
729,   1458,  2430,   3240,   3240,   2160,    720;
2187,  5103,  10206,  17010,  22680,  22680,   15120,   5040;
6561,  17496, 40824,  81648,  136080, 181440,  181440,  120960,  40320; etc.
		

Crossrefs

Programs

  • Magma
    [Factorial(n)/Factorial(n-k)*3^(n-k): k in [0..n], n in [0..10]];
  • Mathematica
    Flatten[Table[n!/(n-k)!*3^(n-k), {n, 0, 10}, {k, 0, n}]]

Formula

T(n,k) = 3^(n-k)*n!/(n-k)! for n>=0, k=0..n.
E.g.f. (by columns): exp(3x)*x^k.

A108869 E.g.f. : exp(6x)/(1-x).

Original entry on oeis.org

1, 7, 50, 366, 2760, 21576, 176112, 1512720, 13781376, 134110080, 1401566976, 15780033792, 191537187840, 2503044135936, 35120982067200, 527284915992576, 8439379765788672, 143486382677852160, 2582856448158007296
Offset: 0

Views

Author

Philippe Deléham, Jul 13 2005

Keywords

Comments

Binomial transform of A080954.
a(n) is the permanent of the n X n matrix with 7's on the diagonal and 1's elsewhere.

Crossrefs

Programs

  • Maple
    a:=n->n!*sum(6^k/k!,k=0..n): seq(a(n),n=0..20); # Emeric Deutsch, Jul 18 2005
    restart:F(x):=exp(6*x)/(1-x): f[0]:=F(x): for n from 1 to 20 do f[n]:=diff(f[n-1],x) od: x:=0: seq(f[n],n=0..18); # Zerinvary Lajos, Apr 03 2009
  • Mathematica
    a[n_] := n! * Sum[6^k/k!, {k, 0, n}]; Array[a, 19, 0] (* Amiram Eldar, Jun 30 2020 *)

Formula

a(n) = n!*Sum_{ k = 0..n } 6^k/k!.
a(n) = Sum_{ k = 0..n } A008290(n, k)*7^k.
a(n) Sum_{ k = 0..n } k!*C(n, k)*6^(n-k).

Extensions

More terms from Emeric Deutsch, Jul 18 2005

A111139 a(n) = n!*Sum_{k=0..n} Fibonacci(k)/k!.

Original entry on oeis.org

0, 1, 3, 11, 47, 240, 1448, 10149, 81213, 730951, 7309565, 80405304, 964863792, 12543229529, 175605213783, 2634078207355, 42145251318667, 716469272418936, 12896446903543432, 245032491167329389, 4900649823346594545
Offset: 0

Views

Author

Vladeta Jovovic, Oct 17 2005

Keywords

Comments

Eigensequence of a triangle with the Fibonacci series as the left border, the natural numbers (1, 2, 3, ...) as the right border; and the rest zeros. - Gary W. Adamson, Aug 01 2016

Crossrefs

Cf. A009102, A009551, A000142, A000166, A000522, A000023, A053486, A010844 (incomplete Gamma function values at other points).

Programs

  • Maple
    a:=n->sum(fibonacci (j)*n!/j!,j=0..n):seq(a(n),n=0..20); # Zerinvary Lajos, Mar 19 2007
  • Mathematica
    f[n_] := n!*Sum[Fibonacci[k]/k!, {k, 0, n}]; Table[ f[n], {n, 0, 20}] (* or *)
    Simplify[ Range[0, 20]!CoefficientList[ Series[2/Sqrt[5]*Exp[x/2]*Sinh[Sqrt[5]*x/2]/(1 - x), {x, 0, 20}], x]] (* Robert G. Wilson v, Oct 21 2005 *)
    Module[{nn=20,fibs,fct},fct=Range[0,nn]!;fibs=Accumulate[ Fibonacci[ Range[ 0,nn]]/fct];Times@@@Thread[{fct,fibs}]] (* Harvey P. Dale, Feb 19 2014 *)
    Round@Table[(E^GoldenRatio Gamma[n+1, GoldenRatio] - E^(1-GoldenRatio) Gamma[n+1, 1-GoldenRatio])/Sqrt[5], {n, 0, 20}] (* Vladimir Reshetnikov, Oct 27 2015 *)
  • PARI
    vector(100, n, n--; n!*sum(k=0, n, fibonacci(k)/k!)) \\ Altug Alkan, Oct 28 2015

Formula

E.g.f.: (2/sqrt(5))*exp(x/2)*sinh(sqrt(5)*x/2)/(1-x).
Recurrence: a(n) = (n+1)*a(n-1) - (n-2)*a(n-2) - (n-2)*a(n-3). - Vaclav Kotesovec, Oct 18 2012
a(n) ~ 2*sqrt(e/5)*sinh(sqrt(5)/2)*n!. - Vaclav Kotesovec, Oct 18 2012
From Vladimir Reshetnikov, Oct 27 2015: (Start)
Let phi=(1+sqrt(5))/2.
a(n) = (phi^n*hypergeom([1,-n], [], 1-phi)-(1-phi)^n*hypergeom([1,-n], [], phi))/sqrt(5).
a(n) = (exp(phi)*Gamma(n+1, phi)-exp^(1-phi)*Gamma(n+1, 1-phi))/sqrt(5), where Gamma(a, x) is the upper incomplete Gamma function.
Gamma(n+1, phi)*exp(phi) = a(n)*phi + A263823(n).
a(n) ~ exp(phi-n)*n^(n+1/2)*sqrt(2*Pi/5)*(1-exp(-sqrt(5))).
(End)

A336998 a(n) = n! * Sum_{d|n} 3^(d - 1) / d!.

Original entry on oeis.org

1, 5, 15, 87, 201, 3123, 5769, 148347, 913761, 11541123, 39975849, 2616723387, 6227552241, 230557039443, 4151870901369, 76980002233707, 355687471142721, 27886053280896963, 121645100796252489, 10474674957482235867, 135117295282596928401, 2811664555920692775603
Offset: 1

Views

Author

Ilya Gutkovskiy, Aug 10 2020

Keywords

Crossrefs

Programs

  • Magma
    A336998:= func< n | Factorial(n)*(&+[3^(d-1)/Factorial(d): d in Divisors(n)]) >;
    [A336998(n): n in [1..40]]; // G. C. Greubel, Jun 26 2024
    
  • Mathematica
    Table[n! Sum[3^(d - 1)/d!, {d, Divisors[n]}], {n, 1, 22}]
    nmax = 22; CoefficientList[Series[Sum[(Exp[3 x^k] - 1)/3, {k, 1, nmax}], {x, 0, nmax}], x] Range[0, nmax]! // Rest
  • PARI
    a(n) = n! * sumdiv(n, d, 3^(d-1)/d!); \\ Michel Marcus, Aug 12 2020
    
  • SageMath
    def A336998(n): return factorial(n)*sum(3^(k-1)/factorial(k) for k in (1..n) if (k).divides(n))
    [A336998(n) for n in range(1,41)] # G. C. Greubel, Jun 26 2024

Formula

E.g.f.: Sum_{k>=1} (exp(3*x^k) - 1) / 3.
a(p) = p! + 3^(p - 1), where p is prime.

A343686 a(0) = 1; a(n) = 3 * n * a(n-1) + Sum_{k=0..n-1} binomial(n,k) * (n-k-1)! * a(k).

Original entry on oeis.org

1, 4, 33, 410, 6796, 140824, 3501782, 101589732, 3368237928, 125634319104, 5206805098752, 237370661584704, 11805144854303760, 636030155604374400, 36903603627294958416, 2294156656214759133024, 152126925169297299197184, 10718105879980375520103936, 799564645068022035991527552
Offset: 0

Views

Author

Ilya Gutkovskiy, Apr 26 2021

Keywords

Crossrefs

Programs

  • Mathematica
    a[0] = 1; a[n_] := a[n] = 3 n a[n - 1] + Sum[Binomial[n, k] (n - k - 1)! a[k], {k, 0, n - 1}]; Table[a[n], {n, 0, 18}]
    nmax = 18; CoefficientList[Series[1/(1 - 3 x + Log[1 - x]), {x, 0, nmax}], x] Range[0, nmax]!

Formula

E.g.f.: 1 / (1 - 3*x + log(1 - x)).
a(n) ~ n! / ((3/c + 2 - c) * (1 - c/3)^n), where c = LambertW(3*exp(2)) = 2.2761339297716461777892556270138... - Vaclav Kotesovec, Apr 26 2021

A296661 a(n) = (exp(k)*Gamma(1+n, k) - exp(-k)*Gamma(1+n, -k))/k! for k = 3.

Original entry on oeis.org

0, 1, 2, 15, 60, 381, 2286, 16731, 133848, 1211193, 12111930, 133290279, 1599483348, 20793814965, 291113409510, 4366705925619, 69867294809904, 1187744054815089, 21379392986671602, 406208467134180927, 8124169342683618540
Offset: 0

Views

Author

Peter Luschny, Dec 18 2017

Keywords

Crossrefs

Programs

  • Maple
    A296661 := n -> (exp(3)*GAMMA(1+n,3) - exp(-3)*GAMMA(1+n,-3))/6:
    seq(simplify(A296661(n)), n=0..20);

Formula

a(n) = (A053486(n) - A010843(n+1))/6. [corrected by Jason Yuen, Nov 23 2024]
D-finite with recurrence a(n) -n*a(n-1) -9*a(n-2) +9*(n-2)*a(n-3)=0. - R. J. Mathar, Sep 29 2020
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