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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A176022 Triangle T(n, k) = A176013(n, k) + A176013(n, n-k+1), read by rows.

Original entry on oeis.org

-2, 3, 3, -7, -18, -7, 25, 96, 96, 25, -121, -650, -800, -650, -121, 721, 5490, 7500, 7500, 5490, 721, -5041, -53067, -92610, -73500, -92610, -53067, -5041, 40321, 564704, 1328096, 987840, 987840, 1328096, 564704, 40321, -362881, -6532164, -20345472, -18373824, -10668672, -18373824, -20345472, -6532164, -362881
Offset: 1

Views

Author

Roger L. Bagula, Apr 06 2010

Keywords

Examples

			Triangle begins as:
     -2;
      3,      3;
     -7,    -18,      -7;
     25,     96,      96,     25;
   -121,   -650,    -800,   -650,   -121;
    721,   5490,    7500,   7500,   5490,     721;
  -5041, -53067,  -92610, -73500, -92610,  -53067,  -5041;
  40321, 564704, 1328096, 987840, 987840, 1328096, 564704, 40321;
		

Crossrefs

Programs

  • Magma
    A176013:= func< n, k | (-1)^n*(Factorial(n)/(k*Factorial(k)))*Binomial(n-1, k-1)*Binomial(n, k-1) >;
    [A176013(n, k) + A176013(n, n-k+1) : k in [1..n], n in [1..12]]; // G. C. Greubel, Feb 15 2021
  • Mathematica
    (* First program *)
    T[n_, m_]:= ((-1)^n*n!/(m*m!))*Binomial[n-1, m-1]*Binomial[n, m-1] + ((-1)^n*n!)/((n-m+1)*(n-m+1)!)*Binomial[n-1, n-m] Binomial[n, n-m];
    Table[T[n, m], {n,10}, {m,n}]//Flatten
    (* Second program *)
    A176013[n_, k_] := (-1)^n*(n!/(k*k!))*Binomial[n-1, k-1]*Binomial[n, k-1];
    T[n_, k_]:= A176013[n, k] + A176013[n, n-k+1];
    Table[T[n, k], {n, 10}, {k, n}]//Flatten (* G. C. Greubel, Feb 15 2021 *)
  • Sage
    def A176013(n, k): return (-1)^n*(factorial(n)/(k*factorial(k)))*binomial(n-1, k-1)*binomial(n, k-1)
    flatten([[A176013(n, k) + A176013(n, n-k+1) for k in (1..n)] for n in (1..12)]) # G. C. Greubel, Feb 15 2021
    

Formula

T(n, k) = ((-1)^n*n!/(k*k!))*binomial(n-1, k-1)*binomial(n, k-1) + ((-1)^n*n!)/((n-k+1)*(n-k+1)!)*binomial(n-1, n-k)*binomial(n, n-k).
From G. C. Greubel, Feb 15 2021: (Start)
T(n, k) = A176013(n, k) + A176013(n, n-k+1), where A176013(n, k) = (-1)^n*(n!/(k*k!))*binomial(n-1, k-1)*binomial(n, k-1).
Sum_{k=1..n} T(n, k) = 2*(-1)^n * n! * Hypergeometric2F2(-n, -(n-1); 2, 2; 1). (End)

Extensions

Edited by G. C. Greubel, Feb 15 2021

A317364 Expansion of e.g.f. exp(2*x/(1 + x)).

Original entry on oeis.org

1, 2, 0, -4, 16, -48, 64, 800, -12288, 127232, -1150976, 9266688, -58726400, 68777984, 7510646784, -207794409472, 4241007640576, -77359570944000, 1321952191971328, -21274345818161152, 313768799799607296, -3838962981483839488, 21775623343518515200, 859024717017756205056
Offset: 0

Views

Author

Ilya Gutkovskiy, Jul 26 2018

Keywords

Comments

Inverse Lah transform of the powers of 2 (A000079).

Crossrefs

Programs

  • Magma
    [n eq 0 select 1 else (-1)^n*Factorial(n)*Evaluate(LaguerrePolynomial(n, -1), 2): n in [0..25]]; // G. C. Greubel, Feb 23 2021
    
  • Maple
    a:= proc(n) option remember; add((-1)^(n-k)*
          n!/k!*binomial(n-1, k-1)*2^k, k=0..n)
        end:
    seq(a(n), n=0..30);  # Alois P. Heinz, Jul 26 2018
  • Mathematica
    nmax = 23; CoefficientList[Series[Exp[2 x/(1 + x)], {x, 0, nmax}], x] Range[0, nmax]!
    nmax = 23; CoefficientList[Series[Product[Exp[-2 (-x)^k], {k, 1, nmax}], {x, 0, nmax}], x] Range[0, nmax]!
    Table[Sum[(-1)^(n-k) Binomial[n-1, k-1] 2^k n!/k!, {k, 0, n}], {n, 0, 23}]
    Join[{1}, Table[2 (-1)^(n+1) n! Hypergeometric1F1[1-n, 2, 2], {n, 23}]]
  • PARI
    a(n) = if (n==0, 1, (-1)^n*n!*pollaguerre(n, -1, 2)); \\ Michel Marcus, Feb 23 2021
  • Sage
    [1 if n==0 else (-1)^n*factorial(n)*gen_laguerre(n, -1, 2) for n in (0..25)] # G. C. Greubel, Feb 23 2021
    

Formula

E.g.f.: Product_{k>=1} exp(-2*(-x)^k).
a(n) = 2*(-1)^(n+1) * n! * Hypergeometric1F1([1-n], [2], 2).
a(n) = Sum_{k=0..n} (-1)^(n-k)*binomial(n-1,k-1)*2^k*n!/k!.
(n^2 + n)*a(n) + 2*n*a(n+1) + a(n+2) = 0. - Robert Israel, Aug 18 2019
From G. C. Greubel, Feb 23 2021: (Start)
a(n) = (-1)^n * n! * Laguerre(n, -1, 2) for n > 0 with a(0) = 1.
a(n) = Sum_{k=0..n} (-1)^(n-k) * A086915(n, k).
a(n) = (-1)^n * Sum_{k=0..n} 2^k * A008297(n, k).
a(n) = Sum_{k=0..n} (-1)^(n-k) * (n-k+1)! * A001263(n, k). (End)

A059374 Triangle read by rows, T(n, k) = Sum_{i=0..n} L'(n, n-i) * binomial(i, k), for k = 0..n-1.

Original entry on oeis.org

1, 3, 2, 13, 18, 6, 73, 156, 108, 24, 501, 1460, 1560, 720, 120, 4051, 15030, 21900, 15600, 5400, 720, 37633, 170142, 315630, 306600, 163800, 45360, 5040, 394353, 2107448, 4763976, 5891760, 4292400, 1834560, 423360, 40320
Offset: 1

Views

Author

Vladeta Jovovic, Jan 28 2001

Keywords

Comments

L'(n, i) are unsigned Lah numbers (Cf. A008297).

Examples

			Triangle begins:
  [1],
  [3, 2],
  [13, 18, 6],
  [73, 156, 108, 24],
  [501, 1460, 1560, 720, 120],
  ...
		

Crossrefs

Cf. T(n, 0) = A000262, A025168 (row sums), A000012 (alternating row sums), A059110.

Programs

  • Mathematica
    t[n_, k_] := Sum[ Binomial[n-1, n-i-1]*n!/(n-i)!*Binomial[i, k], {i, 0, n}]; Table[t[n, k], {n, 1, 8}, {k, 0, n-1}] // Flatten (* Jean-François Alcover, Mar 22 2013 *)
  • PARI
    for(n=1,10, for(k=0,n-1, print1(sum(j=0,n, binomial(j,k)* binomial(n-1,n-j-1)*n!/(n-j)!), ", "))) \\ G. C. Greubel, Jan 29 2018

Formula

E.g.f.: exp(x/(1-(1+y)*x))/(1-(1+y)*x)^2. - Vladeta Jovovic, May 10 2003

A111599 Lah numbers: a(n) = n!*binomial(n-1,8)/9!.

Original entry on oeis.org

1, 90, 4950, 217800, 8494200, 309188880, 10821610800, 371026656000, 12614906304000, 428906814336000, 14668613050291200, 506733905373696000, 17735686688079360000, 630299019222512640000, 22780807409042242560000
Offset: 9

Views

Author

Wolfdieter Lang, Aug 23 2005

Keywords

References

  • Louis Comtet, Advanced Combinatorics, Reidel, 1974, p. 156.
  • John Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 44.

Crossrefs

Column 9 of unsigned A008297 and A111596.
Column 8: A111598.

Programs

  • Maple
    part_ZL:=[S,{S=Set(U,card=r),U=Sequence(Z,card>=1)}, labeled]: seq(count(subs(r=9,part_ZL),size=m),m=9..23) ; # Zerinvary Lajos, Mar 09 2007
  • Mathematica
    Table[n!*Binomial[n-1, 8]/9!, {n, 9, 30}] (* Wesley Ivan Hurt, Dec 10 2013 *)

Formula

E.g.f.: ((x/(1-x))^9)/9!.
a(n) = (n!/9!)*binomial(n-1, 9-1).
If we define f(n,i,x) = Sum_{k=i..n} Sum_{j=i..k} binomial(k,j)*Stirling1(n,k)*Stirling2(j,i)*x^(k-j), then a(n) = (-1)^(n-1)*f(n,9,-9), n >= 9. - Milan Janjic, Mar 01 2009
From Amiram Eldar, May 02 2022: (Start)
Sum_{n>=9} 1/a(n) = 564552*(Ei(1) - gamma) - 264528*e - 873657/35, where Ei(1) = A091725, gamma = A001620, and e = A001113.
Sum_{n>=9} (-1)^(n+1)/a(n) = 28393416*(gamma - Ei(-1)) - 16938720/e - 573537159/35, where Ei(-1) = -A099285. (End)

A111600 Lah numbers: a(n) = n!*binomial(n-1,9)/10!.

Original entry on oeis.org

1, 110, 7260, 377520, 17177160, 721440720, 28857628800, 1121325004800, 42890681433600, 1629845894476800, 61934143990118400, 2364758225077248000, 91043191665474048000, 3543681152517682176000, 139722285442125754368000
Offset: 10

Views

Author

Wolfdieter Lang, Aug 23 2005

Keywords

References

  • Louis Comtet, Advanced Combinatorics, Reidel, 1974, p. 156.
  • John Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 44.

Crossrefs

Column 10 of unsigned A008297 and A111596.
Column 9: A111599.

Programs

  • Mathematica
    Table[n! * Binomial[n - 1, 9]/10!, {n, 10, 25}] (* Amiram Eldar, May 02 2022 *)

Formula

E.g.f.: ((x/(1-x))^10)/10!.
a(n) = (n!/10!)*binomial(n-1, 10-1).
If we define f(n,i,x) = Sum_{k=1..n} Sum_{j=i..k} binomial(k,j) * Stirling1(n,k) * Stirling2(j,i)*x^(k-j) then a(n) = (-1)^n*f(n,10,-10), (n>=10). - Milan Janjic, Mar 01 2009
From Amiram Eldar, May 02 2022: (Start)
Sum_{n>=10} 1/a(n) = 5086710*(gamma - Ei(1)) + 50940*e + 91914449/14, where gamma = A001620, Ei(1) = A091725 and e = A001113.
Sum_{n>=10} (-1)^n/a(n) = 413689770*(gamma - Ei(-1)) - 246749400/e - 3342795017/14, where Ei(-1) = -A099285. (End)

A169654 Triangle T(n, k) = A169643(n, k) - A169653(n, 1) + 1, read by rows.

Original entry on oeis.org

1, 1, 1, 1, -4, 1, 1, 24, 24, 1, 1, -138, -118, -138, 1, 1, 1110, 780, 780, 1110, 1, 1, -10120, -8188, -3358, -8188, -10120, 1, 1, 100856, 101976, 30240, 30240, 101976, 100856, 1, 1, -1088710, -1332574, -512062, -60478, -512062, -1332574, -1088710, 1
Offset: 1

Views

Author

Roger L. Bagula, Apr 05 2010

Keywords

Examples

			Triangle begins as:
  1;
  1,        1;
  1,       -4,        1;
  1,       24,       24,       1;
  1,     -138,     -118,    -138,      1;
  1,     1110,      780,     780,   1110,       1;
  1,   -10120,    -8188,   -3358,  -8188,  -10120,        1;
  1,   100856,   101976,   30240,  30240,  101976,   100856,        1;
  1, -1088710, -1332574, -512062, -60478, -512062, -1332574, -1088710,        1;
  1, 12700890, 18147240, 9132480, 816480,  816480,  9132480, 18147240, 12700890, 1;
		

Crossrefs

Programs

  • Magma
    A001263:= func< n,k | Binomial(n-1, k-1)*Binomial(n,k-1)/k >;
    A169653:= func< n,k | (-1)^n*A001263(n, k)*(Factorial(k) + Factorial(n-k+1)) >;
    A169654:= func< n,k | A169653(n, k) - A169653(n, 1) + 1 >;
    [A169654(n, k): k in [1..n], n in [1..10]]; // G. C. Greubel, Feb 23 2021
  • Mathematica
    t[n_, m_] = (-1)^n*(n!/m!)*Binomial[n-1, m-1];
    T[n_, m_] = t[n, m] + t[n, n-m+1] - (-1)^n*(n! + 1) + 1;
    Table[T[n,k], {n,12}, {k,n}]//Flatten (* modified by G. C. Greubel, Feb 23 2021 *)
  • Sage
    def A001263(n, k): return binomial(n-1, k-1)*binomial(n,k-1)/k
    def A169653(n, k): return (-1)^n*A001263(n, k)*(factorial(k) + factorial(n-k+1))
    def A169654(n, k): return A169653(n, k) - A169653(n, 1) + 1
    flatten([[A169654(n,k) for k in (1..n)] for n in (1..10)]) # G. C. Greubel, Feb 23 2021
    

Formula

T(n, k) = t(n, k) + t(n, n-k+1) - t(n, 1) - t(n, n) + 1, where t(n, k) = (-1)^n*(n!/k!)*binomial(n-1, k-1).
T(n, k) = A008297(n,k) + A008297(n,n-k+1) - (A008297(n,1) + A008297(n,n)) + 1.
From G. C. Greubel, Feb 23 2021: (Start)
T(n, k) = A169653(n, k) - A169653(n, 1) + 1
T(n, k) = A169653(n, k) - (-1)^n * (n! + 1) + 1.
T(n, k) = (-1)^n * (A105278(n, k) + A105278(n, n-k+1) - (n! + 1) + (-1)^n).
Sum_{k=1..n} T(n, k) = (-1)^n *(2 * A000262(n) - n*(n! + 1) + (-1)^n * n). (End)

Extensions

Edited by G. C. Greubel, Feb 23 2021

A169656 Triangle, read by rows, T(n, k) = (-1)^n*(n!/k!)^2*binomial(n-1, k-1).

Original entry on oeis.org

-1, 4, 1, -36, -18, -1, 576, 432, 48, 1, -14400, -14400, -2400, -100, -1, 518400, 648000, 144000, 9000, 180, 1, -25401600, -38102400, -10584000, -882000, -26460, -294, -1, 1625702400, 2844979200, 948326400, 98784000, 3951360, 65856, 448, 1
Offset: 1

Views

Author

Roger L. Bagula, Apr 05 2010

Keywords

Comments

Row sums are: {-1, 5, -55, 1057, -31301, 1319581, -74996755, 5521809665, -510921831817, 58003632177301, ...}.

Examples

			Triangle begins as:
         -1;
          4,         1;
        -36,       -18,        -1;
        576,       432,        48,       1;
     -14400,    -14400,     -2400,    -100,     -1;
     518400,    648000,    144000,    9000,    180,    1;
  -25401600, -38102400, -10584000, -882000, -26460, -294, -1;
		

Crossrefs

Cf. A008297.

Programs

  • GAP
    F:=Factorial;; Flat(List([1..10], n-> List([1..n], k-> (-1)^n*(F(n)/F(k) )^2*Binomial(n-1, k-1) ))); # G. C. Greubel, Nov 28 2019
  • Magma
    F:=Factorial; [(-1)^n*(F(n)/F(k))^2*Binomial(n-1, k-1): k in [1..n], n in [1..10]]; // G. C. Greubel, Nov 28 2019
    
  • Maple
    seq(seq( (-1)^n*(n!/k!)^2*binomial(n-1, k-1), k=1..n), n=1..10); # G. C. Greubel, Nov 28 2019
  • Mathematica
    T[n_, k_]:= (-1)^n*(n!/k!)^2*Binomial[n-1, k-1]; Table[T[n, k], {n,10}, {k,n}]//Flatten
  • PARI
    T(n,k) = (-1)^n*(n!/k!)^2*binomial(n-1, k-1); \\ G. C. Greubel, Nov 28 2019
    
  • Sage
    f=factorial; [[(-1)^n*(f(n)/f(k))^2*binomial(n-1, k-1) for k in (1..n)] for n in (1..10)] # G. C. Greubel, Nov 28 2019
    

Formula

T(n, k) = (-1)^n * (n!/k!)^2 * binomial(n-1, k-1).

Extensions

Edited by G. C. Greubel, Nov 28 2019

A169658 Triangle, read by rows, defined by T(n, k) = b(n, k) + b(n, n-k+1) - (b(n,1) + b(n,n)) + 1, where b(n, k) = (-1)^n*(n!/k!)^2 *binomial(n-1, k-1).

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, -96, -96, 1, 1, -98, 9602, -98, 1, 1, 129780, -365400, -365400, 129780, 1, 1, -12701092, 14791142, 23637602, 14791142, -12701092, 1, 1, 1219277248, -677310144, -1522967040, -1522967040, -677310144, 1219277248, 1
Offset: 1

Views

Author

Roger L. Bagula, Apr 05 2010

Keywords

Comments

Row sums are: {1, 2, 4, -190, 9408, -471238, 27817704, -1961999870, 163293385984, -15674630045398, ...}.

Examples

			Triangle begins as:
  1;
  1,         1;
  1,         2,        1;
  1,       -96,      -96,        1;
  1,       -98,     9602,      -98,        1;
  1,    129780,  -365400,  -365400,   129780,         1;
  1, -12701092, 14791142, 23637602, 14791142, -12701092, 1;
		

Crossrefs

Cf. A008297.

Programs

  • Magma
    b:= func< n,k | (-1)^n*(Factorial(n)/Factorial(k))^2*Binomial(n-1, k-1) >;
    [[b(n, k) +b(n, n-k+1) -b(n,1) -b(n,n) +1: k in [1..n]]: n in [1..10]]; // G. C. Greubel, May 20 2019
    
  • Mathematica
    L[n_, m_] = (-1)^n*(n!/m!)^2*Binomial[n-1, m-1];
    t[n_, m_] = L[n, m] + L[n, n-m+1];
    Table[t[n, m] - t[n, 1] + 1, {n, 1, 10}, {m, 1, n}]//Flatten
  • PARI
    b(n, k) = (-1)^n*(n!/k!)^2 *binomial(n-1, k-1);
    t(n, k) = b(n, k) + b(n, n-k+1);
    for(n=1, 10, for(k=1, n, print1(t(n,k) - t(n,1) + 1, ", "))) \\ G. C. Greubel, May 20 2019
    
  • Sage
    def b(n, k): return (-1)^n*factorial(n-k)^2*binomial(n,k)^2*binomial(n-1, k-1)
    def t(n, k): return b(n, k) + b(n, n-k+1)
    [[t(n,k) - t(n,1) + 1 for k in (1..n)] for n in (1..10)] # G. C. Greubel, May 20 2019

Formula

T(n, k) = b(n, k) + b(n, n-k+1) - b(n, n) - b(n, 1) + 1, where b(n, k) = (-1)^n*(n!/m!)^2 *binomial(n-1, k-1), where 1 <= k <= n, n >= 1.

Extensions

Edited by G. C. Greubel, May 20 2019

A173227 Partial sums of A000262.

Original entry on oeis.org

1, 2, 5, 18, 91, 592, 4643, 42276, 436629, 5033182, 63974273, 888047414, 13358209647, 216334610860, 3751352135263, 69325155322184, 1359759373992105, 28206375825238458, 616839844140642301, 14181213537729200474, 341879141423814854915, 8623032181189674581256
Offset: 0

Views

Author

Jonathan Vos Post, Feb 13 2010

Keywords

Comments

Partial sums of the number of "sets of lists": number of partitions of {1,..,n} into any number of lists, where a list means an ordered subset. The subsequence of primes begins: 2, 5, 4643, 616839844140642301.

Examples

			a(20) = 1 + 1 + 3 + 13 + 73 + 501 + 4051 + 37633 + 394353 + 4596553 + 58941091 + 824073141 + 12470162233 + 202976401213 + 3535017524403 + 65573803186921 + 1290434218669921 + 26846616451246353 + 588633468315403843 + 13564373693588558173 + 327697927886085654441.
		

Crossrefs

Programs

  • Magma
    l:= func< n,b | Evaluate(LaguerrePolynomial(n), b) >;
    [n eq 0 select 1 else 1 + (&+[ Factorial(j)*( l(j,-1) - l(j-1,-1) ): j in [1..n]]): n in [0..25]]; // G. C. Greubel, Mar 09 2021
  • Maple
    b:= proc(n) option remember; `if`(n=0, 1, add(
           b(n-j)*j!*binomial(n-1, j-1), j=1..n))
        end:
    a:= proc(n) option remember; b(n)+`if`(n>0, a(n-1), 0) end:
    seq(a(n), n=0..25);  # Alois P. Heinz, May 11 2016
  • Mathematica
    With[{m = 25}, CoefficientList[Exp[x/(1-x)] + O[x]^m, x] Range[0, m-1]!// Accumulate] (* Jean-François Alcover, Nov 21 2020 *)
    Table[1 +Sum[j!*(LaguerreL[j, -1] -LaguerreL[j-1, -1]), {j,n}], {n,0,30}] (* G. C. Greubel, Mar 09 2021 *)
  • Sage
    [1 + sum(factorial(j)*(gen_laguerre(j,0,-1) - gen_laguerre(j-1,0,-1)) for j in (1..n)) for n in (0..30)] # G. C. Greubel, Mar 09 2021
    

Formula

From Vaclav Kotesovec, Oct 25 2016: (Start)
a(n) = 2*n*a(n-1) - (n^2 - n + 1)*a(n-2) + (n-2)*(n-1)*a(n-3).
a(n) ~ exp(2*sqrt(n)-n-1/2)*n^(n-1/4)/sqrt(2) * (1 - 5/(48*sqrt(n))).
(End)
a(n) = 1 + Sum_{j=1..n} j!*( LaguerreL(j,-1) - LaguerreL(j-1,-1) ). - G. C. Greubel, Mar 09 2021

A276960 a(n) = A000262(n)^2.

Original entry on oeis.org

1, 1, 9, 169, 5329, 251001, 16410601, 1416242689, 155514288609, 21128299481809, 3474052208270281, 679096541717605881, 155504946117339546289, 41199419449380747871369, 12496348897836314700506409
Offset: 0

Views

Author

Emanuele Munarini, Sep 27 2016

Keywords

Crossrefs

Programs

  • Mathematica
    Table[HypergeometricPFQ[{-n+1,-n},{},1]^2,{n,0,100}]
  • Maxima
    makelist(hypergeometric([-n+1,-n],[],1)^2,n,0,12);

Formula

Recurrence: (2*n+3)*a(n+3)-(2*n+5)*(3*n^2+13*n+13)*a(n+2)+(n+2)*(n+1)*(2*n+3)*(3*n^2+13*n+13)*a(n+1)-n^2*(n+1)^3*(n+2)*(2 n+5)*a(n) = 0.
Asymptotic: a(n) ~ exp(-2*n+4*sqrt(n)-1)*n^(2*n-1/2)/2 * (1 - 5/(24*sqrt(n)) - 35/(1152*n)).
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