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.

A001714 Generalized Stirling numbers.

Original entry on oeis.org

1, 25, 445, 7140, 111769, 1767087, 28699460, 483004280, 8460980836, 154594537812, 2948470152264, 58696064973000, 1219007251826064, 26390216795274288, 594982297852020288, 13955257961738192448, 340154857108405040256, 8606960634143667938688
Offset: 0

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Author

N. J. A. Sloane

Keywords

Comments

The asymptotic expansion of the higher-order exponential integral E(x,m=5,n=3) ~ exp(-x)/x^5*(1 - 25/x + 445/x^2 - 7140/x^3 + 111769/x^4 - ...) leads to the sequence given above. See A163931 for E(x,m,n) information and A163932 for a Maple procedure for the asymptotic expansion. - Johannes W. Meijer, Oct 20 2009
From Petros Hadjicostas, Jun 13 2020: (Start)
For nonnegative integers n, m and complex numbers a, b (with b <> 0), the numbers R_n^m(a,b) were introduced by Mitrinovic (1961) and Mitrinovic and Mitrinovic (1962) using slightly different notation.
These numbers are defined via the g.f. Product_{r=0..n-1} (x - (a + b*r)) = Sum_{m=0..n} R_n^m(a,b)*x^m for n >= 0.
As a result, R_n^m(a,b) = R_{n-1}^{m-1}(a,b) - (a + b*(n-1))*R_{n-1}^m(a,b) for n >= m >= 1 with R_0^0(a,b) = 1, R_1^0(a,b) = a, R_1^1(a,b) = 1, and R_n^m(a,b) = 0 for n < m.
With a = 0 and b = 1, we get the Stirling numbers of the first kind S1(n,m) = R_n^m(a=0, b=1) = A048994(n,m) for n, m >= 0.
We have R_n^m(a,b) = Sum_{k=0}^{n-m} (-1)^k * a^k * b^(n-m-k) * binomial(m+k, k) * S1(n, m+k) for n >= m >= 0.
For the current sequence, a(n) = R_{n+4}^4(a=-3, b=-1) for n >= 0. (End)

References

  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Crossrefs

Cf. A001711, A001712, A001713, A048994, A163931, A163932.

Programs

  • Mathematica
    nn = 24; t = Range[0, nn]! CoefficientList[Series[Log[1 - x]^4/(24*(1 - x)^3), {x, 0, nn}], x]; Drop[t, 4] (* T. D. Noe, Aug 09 2012 *)

Formula

a(n) = Sum_{k=0..n} (-1)^(n+k) * binomial(k+4, 4) * 3^k * Stirling1(n+4, k+4). - Borislav Crstici (bcrstici(AT)etv.utt.ro), Jan 26 2004
If we define f(n,i,a) = Sum_{k=0..n-i} binomial(n,k) * Stirling1(n-k,i) * Product_{j=0..k-1} (-a-j), then a(n-4) = |f(n,4,3)| for n >= 4. - Milan Janjic, Dec 21 2008
From Petros Hadjicostas, Jun 14 2020: (Start)
a(n) = [x^4] Product_{r=0}^{n+3} (x + 3 + r) = (Product_{r=0}^{n+3} (r+3)) * Sum_{0 <= i < j < k < m <= n+3} 1/((3+i)*(3+j)*(3+k)*(3+m)).
E.g.f.: Sum_{n>=0} a(n)*x^(n+4)/(n+4)! = (log(1 - x))^4/(1 - x)^3/24.
Since a(n) = R_{n+4}^4(a=-3, b=-1), A001713(n) = R_{n+3}^3(a=-3,b=-1), A001712(n) = R_{n+2}^2(a=-3, b=-1), and A001711(n) = R_{n+1}^1(a=-3,b=-1), the equation R_{n+4}^4(a=-3,b=-1) = R_{n+3}^3(a=-3,b=-1) + (n+6)*R_{n+3}^4(a=-3,b=-1) implies the following:
(i) a(n) = A001713(n) + (n+6)*a(n-1) for n >= 1.
(ii) a(n) = A001712(n) + (2*n+11)*a(n-1) - (n+5)^2*a(n-2) for n >= 2.
(iii) a(n) = A001711(n) + 3*(n+5)*a(n-1) - (3*n^2+27*n+61)*a(n-2) + (n+4)^3*a(n-3) for n >= 3.
(iv) a(n) = (n+2)!/2 + 2*(2*n+9)*a(n-1) - (6*n^2+48*n+97)*a(n-2) + (2*n+7)*(2*n^2+14*n+25)*a(n-3) - (n+3)^4*a(n-4) for n >= 4.
(v) By taking the difference a(n) - (n+2)*a(n-1), and using (iv) above, we get a 5th-order linear recurrence with polynomial coefficients of degree at most 5. We omit the details. (End)

Extensions

More terms from Borislav Crstici (bcrstici(AT)etv.utt.ro), Jan 26 2004

A001722 Generalized Stirling numbers.

Original entry on oeis.org

1, 18, 251, 3325, 44524, 617624, 8969148, 136954044, 2201931576, 37272482280, 663644774880, 12413008539360, 243533741849280, 5003753991174720, 107497490419296000, 2410964056571616000, 56366432074677312000, 1371711629236971456000, 34699437370290760704000
Offset: 0

Views

Author

N. J. A. Sloane

Keywords

Comments

The asymptotic expansion of the higher order exponential integral E(x,m=3,n=5) ~ exp(-x)/x^3*(1 - 18/x + 251/x^2 - 3325/x^3 + 44524/x^4 - 617624/x^5 + ... ) leads to the sequence given above. See A163931 and A163932 for more information. - Johannes W. Meijer, Oct 20 2009

References

  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Programs

  • Mathematica
    Table[Sum[(-1)^(n + k)*Binomial[k + 2, 2]*5^k*StirlingS1[n + 2, k + 2], {k, 0, n}], {n, 0, 20}] (* T. D. Noe, Aug 10 2012 *)

Formula

a(n) = Sum_{k=0..n} (-1)^(n+k)*binomial(k+2, 2)*5^k*Stirling1(n+2, k+2). - Borislav Crstici (bcrstici(AT)etv.utt.ro), Jan 26 2004
If we define f(n,i,a) = Sum_{k=0..n-i} binomial(n,k)*Stirling1(n-k,i)*Product_{j=0..k-1} (-a-j), then a(n-2) = |f(n,2,5)|, for n >= 2. - Milan Janjic, Dec 21 2008

Extensions

More terms from Borislav Crstici (bcrstici(AT)etv.utt.ro), Jan 26 2004

A001724 Generalized Stirling numbers.

Original entry on oeis.org

1, 35, 835, 17360, 342769, 6687009, 131590430, 2642422750, 54509190076, 1159615530788, 25497032420496, 580087776122400, 13662528306823824, 333132304121991504, 8407011584355624288, 219490450157530821024, 5925108461354500651776, 165275526944869750483200
Offset: 0

Views

Author

N. J. A. Sloane

Keywords

Comments

The asymptotic expansion of the higher order exponential integral E(x,m=5,n=5) ~ exp(-x)/x^5*(1 - 35/x + 835/x^2 - 17360/x^3 + 342769/x^4 - ...) leads to the sequence given above. See A163931 for E(x,m,n) information and A163932 for a Maple procedure for the asymptotic expansion. - Johannes W. Meijer, Oct 20 2009

References

  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Programs

  • Mathematica
    Table[Sum[(-1)^(n + k)*Binomial[k + 4, 4]*5^k*StirlingS1[n + 4, k + 4], {k, 0, n}], {n, 0, 20}] (* T. D. Noe, Aug 10 2012 *)
  • PARI
    a(n) = sum(k=0, n, (-1)^(n+k)*binomial(k+4, 4)*5^k*stirling(n+4, k+4, 1)) \\ Michel Marcus, Jan 20 2016

Formula

a(n) = sum((-1)^(n+k)*binomial(k+4, 4)*5^k*stirling1(n+4, k+4), k=0..n). - Borislav Crstici (bcrstici(AT)etv.utt.ro), Jan 26 2004
E.g.f.: (6-156*log(1-x)+753*log(1-x)^2-1066*log(1-x)^3+420*log(1-x)^4)/(6*(1-x)^9). - Vladeta Jovovic, Mar 01 2004
If we define f(n,i,a)=sum(binomial(n,k)*stirling1(n-k,i)*product(-a-j,j=0..k-1),k=0..n-i), then a(n-4) = |f(n,4,5)|, for n>=4. - Milan Janjic, Dec 21 2008

Extensions

More terms from Borislav Crstici (bcrstici(AT)etv.utt.ro), Jan 26 2004

A051525 Third unsigned column of triangle A051338.

Original entry on oeis.org

0, 0, 1, 21, 335, 5000, 74524, 1139292, 18083484, 299705400, 5198985576, 94461323616, 1797180658272, 35776357096896, 744402741205824, 16169795109262080, 366214212167489280, 8636605663418933760
Offset: 0

Views

Author

Wolfdieter Lang

Keywords

Comments

From Johannes W. Meijer, Oct 20 2009: (Start)
The asymptotic expansion of the higher order exponential integral E(x,m=3,n=6) ~ exp(-x)/x^3*(1 - 21/x + 335/x^2 - 5000/x^3 + 74524/x^4 - 1139292/x^5 + ...) leads to the sequence given above. See A163931 and A163932 for more information.
(End)

References

  • Mitrinovic, D. S. and Mitrinovic, R. S. see reference given for triangle A051338.

Crossrefs

Cf. A001725 (m=0), A051524 (m=1) unsigned columns.

Formula

a(n) = A051338(n, 2)*(-1)^n; e.g.f.: (log(1-x))^2/(2*(1-x)^6).
If we define f(n,i,a)=sum(binomial(n,k)*stirling1(n-k,i)*product(-a-j,j=0..k-1),k=0..n-i), then a(n) = |f(n,2,6)|, for n>=1. - Milan Janjic, Dec 21 2008

A051546 Third unsigned column of triangle A051339.

Original entry on oeis.org

0, 0, 1, 24, 431, 7155, 117454, 1961470, 33775244, 603682596, 11235811536, 218055250512, 4413843664416, 93156324734304, 2048591287486080, 46898664421553280, 1116592842912341760, 27618683992928743680
Offset: 0

Views

Author

Wolfdieter Lang

Keywords

Comments

From Johannes W. Meijer, Oct 20 2009: (Start)
The asymptotic expansion of the higher order exponential integral E(x,m=3,n=7) ~ exp(-x)/x^3*(1 - 24/x + 431/x^2 - 7155/x^3 + 117454/x^4 + ...) leads to the sequence given above. See A163931 and A163932 for more information.
(End)

References

  • Mitrinovic, D. S. and Mitrinovic, R. S. see reference given for triangle A051339.

Crossrefs

Cf. A001730 (m=0), A051545 (m=1) unsigned columns.

Formula

a(n) = A051339(n, 2)*(-1)^n; e.g.f.: (log(1-x))^2/(2*(1-x)^7).
If we define f(n,i,a)=sum(binomial(n,k)*stirling1(n-k,i)*product(-a-j,j=0..k-1),k=0..n-i), then a(n) = |f(n,2,7)|, for n>=1. - Milan Janjic, Dec 21 2008

A051561 Third unsigned column of triangle A051379.

Original entry on oeis.org

0, 0, 1, 27, 539, 9850, 176554, 3197348, 59354028, 1137868848, 22614500016, 466814750688, 10015620672672, 223359393479040, 5175622796192640, 124533006364442880, 3109120944743427840, 80473740053567016960
Offset: 0

Views

Author

Wolfdieter Lang

Keywords

Comments

From Johannes W. Meijer, Oct 20 2009: (Start)
The asymptotic expansion of the higher order exponential integral E(x,m=3,n=8) ~ exp(-x)/x^3*(1 - 27/x + 539/x^2 - 9850/x^3 + 176554/x^4 + ...) leads to the sequence given above. See A163931 and A163932 for more information.
(End)

References

  • Mitrinovic, D. S. and Mitrinovic, R. S. see reference given for triangle A051379.

Crossrefs

Cf. A049388 (m=0), A051560 (m=1) unsigned columns.

Programs

  • Mathematica
    With[{nn=20},CoefficientList[Series[(Log[1-x])^2/(2(1-x)^8),{x,0,nn}],x] Range[0,nn]!] (* Harvey P. Dale, Jul 10 2013 *)

Formula

a(n) = A051379(n, 2)*(-1)^n; e.g.f.: ((log(1-x))^2)/(2*(1-x)^8).
If we define f(n,i,a)=sum(binomial(n,k)*stirling1(n-k,i)*product(-a-j,j=0..k-1),k=0..n-i), then a(n) = |f(n,2,8)|, for n>=1. - Milan Janjic, Dec 21 2008

A051563 Third unsigned column of triangle A051380.

Original entry on oeis.org

0, 0, 1, 30, 659, 13145, 255424, 4985316, 99236556, 2030997852, 42924478536, 938984014584, 21283428847680, 500043968498880, 12176238355176960, 307176581692097280, 8023946251816984320, 216880826334455750400
Offset: 0

Views

Author

Wolfdieter Lang

Keywords

Comments

From Johannes W. Meijer, Oct 20 2009: (Start)
The asymptotic expansion of the higher order exponential integral E(x,m=3,n=9) ~ exp(-x)/x^3*(1 - 30/x + 659/x^2 - 13145/x^3 + 255424/x^4 + ...) leads to the sequence given above. See A163931 and A163932 for more information.
(End)

References

  • Mitrinovic, D. S. and Mitrinovic, R. S. see reference given for triangle A051380.

Crossrefs

Cf. A049389 (m=0), A051562 (m=1) unsigned columns.

Formula

a(n) = A051380(n, 2)*(-1)^n; e.g.f.: ((log(1-x))^2)/(2*(1-x)^9).
If we define f(n,i,a)=sum(binomial(n,k)*stirling1(n-k,i)*product(-a-j,j=0..k-1),k=0..n-i), then a(n) = |f(n,2,9)|, for n>=1. - Milan Janjic, Dec 21 2008

A051565 Third unsigned column of triangle A051523.

Original entry on oeis.org

0, 0, 1, 33, 791, 17100, 358024, 7491484, 159168428, 3463513704, 77559615576, 1792139785920, 42789106278720, 1056302350122240, 26964471256888320, 711643650545422080, 19410244660543737600, 546854985563699289600
Offset: 0

Views

Author

Wolfdieter Lang

Keywords

Comments

From Johannes W. Meijer, Oct 20 2009: (Start)
The asymptotic expansion of the higher order exponential integral E(x,m=3,n=10) ~ exp(-x)/x^3*(1 - 33/x + 791/x^2 - 17100/x^3 + 358024/x^4 + ...) leads to the sequence given above. See A163931 and A163932 for more information.
(End)

References

  • Mitrinovic, D. S. and Mitrinovic, R. S. see reference given for triangle A051523.

Crossrefs

Cf. A049398 (m=0), A051564 (m=1) unsigned columns.

Formula

a(n) = A051523(n, 2)*(-1)^n; e.g.f.: ((log(1-x))^2)/(2*(1-x)^10).
If we define f(n,i,a)=sum(binomial(n,k)*stirling1(n-k,i)*product(-a-j,j=0..k-1),k=0..n-i), then a(n) = |f(n,2,10)|, for n>=1. - Milan Janjic, Dec 21 2008
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