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.

Showing 1-10 of 20 results. Next

A255322 a(n) = Product_{k=0..n} (k^2)!.

Original entry on oeis.org

1, 1, 24, 8709120, 182219087869378560000, 2826438545846116156142906806150103040000000000, 1051416277636507481568264360276689674557030810000137484550133942059008000000000000000000
Offset: 0

Views

Author

Vaclav Kotesovec, Feb 21 2015

Keywords

Comments

Partial products of A088020. - Michel Marcus, Jul 06 2019

Crossrefs

Programs

  • Mathematica
    Table[Product[(k^2)!, {k, 0, n}], {n, 0, 10}]
    FoldList[Times,(Range[0,6]^2)!] (* Harvey P. Dale, Jan 30 2022 *)
    Table[(n^2)!^(n+1) / Product[j^(Ceiling[Sqrt[j]]), {j, 1, n^2}], {n, 0, 6}] (* Vaclav Kotesovec, Apr 23 2024 *)
    Table[(n^2)!^n * (n!)^2 / Product[j^(Floor[Sqrt[j]]), {j, 1, n^2}], {n, 0, 6}] (* Vaclav Kotesovec, Apr 23 2024 *)
  • PARI
    {a(n) = prod(k=1, n, (k^2)!)} \\ Seiichi Manyama, Jul 06 2019

Formula

a(n) ~ c * n^((2*n + 1)*(2*n^2 + 2*n + 3)/6) * (2*Pi)^(n/2) / exp(5*n^3/9 + n^2/2 + n), where c = A255504 = 3.048330306522348566911920417337613015885313475... .
From Vaclav Kotesovec, Apr 23 2024: (Start)
a(n) = Product_{j=1..n^2} j^(n - ceiling(sqrt(j)) + 1).
a(n) = (n^2)!^n * (n!)^2 / Product_{j=1..n^2} j^(floor(sqrt(j))). (End)

A039622 Number of n X n Young tableaux.

Original entry on oeis.org

1, 1, 2, 42, 24024, 701149020, 1671643033734960, 475073684264389879228560, 22081374992701950398847674830857600, 220381378415074546123953914908618547085974856000, 599868742615440724911356453304513631101279740967209774643120000
Offset: 0

Views

Author

Keywords

Comments

Number of arrangements of 1,2,...,n^2 in an n X n array such that each row and each column is increasing. The problem for a 5 X 5 array was recently posed and solved in the College Mathematics Journal. See the links.
This is the factor g_n that appears in a conjectured formula for 2n-th moment of the Riemann zeta function on the critical line. (See Conrey articles.) - Michael Somos, Apr 15 2003 [Comment revised by N. J. A. Sloane, Jun 21 2016]
Number of linear extensions of the n X n lattice. - Mitch Harris, Dec 27 2005

Examples

			Using the hook length formula, a(4) = (16)!/(7*6^2*5^3*4^4*3^3*2^2) = 24024.
		

References

  • M. du Sautoy, The Music of the Primes, Fourth Estate / HarperCollins, 2003; see p. 284.

Crossrefs

Main diagonal of A060854.
Also a(2)=A000108(2), a(3)=A005789(3), a(4)=A005790(4), a(5)=A005791(5).

Programs

  • Magma
    A039622:= func< n | n eq 0 select 1 else Factorial(n^2)*(&*[Factorial(j)/Factorial(n+j): j in [0..n-1]]) >;
    [A039622(n): n in [0..12]]; // G. C. Greubel, Apr 21 2021
    
  • Maple
    a:= n-> (n^2)! *mul(k!/(n+k)!, k=0..n-1):
    seq(a(n), n=0..12);  # Alois P. Heinz, Apr 10 2012
  • Mathematica
    a[n_]:= (n^2)!*Product[ k!/(n+k)!, {k, 0, n-1}]; Table[ a[n], {n, 0, 12}] (* Jean-François Alcover, Dec 06 2011, after Pari *)
  • PARI
    a(n)=(n^2)!*prod(k=0,n-1,k!/(n+k)!)
    
  • Sage
    def A039622(n): return factorial(n^2)*product( factorial(j)/factorial(n+j) for j in (0..n-1))
    [A039622(n) for n in (0..12)] # G. C. Greubel, Apr 21 2021

Formula

a(n) = (n^2)! / Product_{k=1..2n-1} k^(n - |n-k|).
a(n) = 0!*1!*...*(k-1)! *(k*n)! / ( n!*(n+1)!*...*(n+k-1)! ) for k=n.
a(n) = A088020(n)/A107254(n) = A088020(n)*A000984(n)/A079478(n). - Henry Bottomley, May 14 2005
a(n) = A153452(prime(n)^n). - Naohiro Nomoto, Jan 01 2009
a(n) ~ sqrt(Pi) * n^(n^2+11/12) * exp(n^2/2+1/12) / (A * 2^(2*n^2-7/12)), where A = 1.28242712910062263687534256886979... is the Glaisher-Kinkelin constant (see A074962). - Vaclav Kotesovec, Feb 10 2015
From Peter Luschny, May 20 2019: (Start)
a(n) = (G(1+n)*G(2+n)^(2-n)*(n^2)!*(G(3+n)/Gamma(2+n))^(n-1))/(G(1+2*n)*n!) where G(x) is the Barnes G function.
a(n) = A127223(n) / A107252(n). (End)
a(n) = (Gamma(n^2 +1)/Gamma(n+1))*(G(n+1)*G(n+2)/G(2*n+1)), where G(n) is the Barnes G-function. - G. C. Greubel, Apr 21 2021
a(n+2) = (n+2) * A060856(n+1) for n >= 0. - Tom Copeland, May 30 2022

A089484 Number of positions of the 15-puzzle at a distance of n moves from an initial state with the empty square in one of the corners, in the single-tile metric.

Original entry on oeis.org

1, 2, 4, 10, 24, 54, 107, 212, 446, 946, 1948, 3938, 7808, 15544, 30821, 60842, 119000, 231844, 447342, 859744, 1637383, 3098270, 5802411, 10783780, 19826318, 36142146, 65135623, 116238056, 204900019, 357071928, 613926161, 1042022040
Offset: 0

Views

Author

Hugo Pfoertner, Nov 25 2003

Keywords

Comments

The single-tile metric counts moves of individual tiles as 1 move. Moving multiple tiles at once counts as more than one move, e.g. simultaneously sliding 3 tiles along a row or column counts as 3 moves.
The last term is a(80). The total number of possible configurations of an m X m sliding block puzzle is (m*m)!/2 = A088020(4)/2, therefore, Sum_i (i=0..80) a(i) = 16!/2 = 10461394944000.

References

Crossrefs

Programs

  • Python
    # alst(), moves(), swap() in A089473
    start, shape = "-123456789ABCDEF", (4, 4)
    alst(start, shape, v=True) # Michael S. Branicky, Dec 31 2020

Extensions

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Oct 19 2006
Name edited by Ben Whitmore, Aug 02 2024

A088021 a(n) = (n^2)!/(n!)^2.

Original entry on oeis.org

1, 1, 6, 10080, 36324288000, 1077167364120207360000, 717579719887926731226850787328000000, 23946596436219275985459662514223331478629410406400000000
Offset: 0

Views

Author

Hugo Pfoertner, Sep 18 2003

Keywords

Comments

Based on an observation of Hugo Pfoertner, W. Edwin Clark conjectured and Xiang-dong Hou proved that (n^2)!/(n!)^2 gives the number of distinct determinants of the generic n X n matrix whose entries are n^2 different indeterminates under all (n^2)! permutations of the entries.
Using J. T. Schwarz's Sparse Zeros Lemma this implies that for any positive integer n there is an n X n matrix A with positive integer entries such that the set of determinant values obtained from A by permuting the elements of A is (n^2)!/(n!)^2.
Moreover, for any entries, no larger number of determinants can be obtained. In fact, by the Sparse Zeros Lemma one can select the entries of A from any sufficiently large subset of real numbers.

Crossrefs

Programs

  • Magma
    [Factorial(n^2)/Factorial(n)^2: n in [0..10]]; // Vincenzo Librandi, May 31 2011

Formula

a(n) = A088020(n)/A001044(n).

A090031 Number of configurations of the 5 X 5 variant of sliding block 15-puzzle ("24-puzzle") that require a minimum of n moves to be reached, starting with the empty square in one of the corners.

Original entry on oeis.org

1, 2, 4, 10, 26, 64, 159, 366, 862, 1904, 4538, 10238, 24098, 53186, 123435, 268416, 616374, 1326882, 3021126, 6438828, 14524718, 30633586, 68513713, 143106496, 317305688, 656178756, 1442068376, 2951523620, 6427133737, 13014920506, 28070588413, 56212979470, 120030667717
Offset: 0

Views

Author

Hugo Pfoertner, Nov 25 2003

Keywords

Comments

The 15-block puzzle is often referred to (incorrectly) as Sam Loyd's 15-Puzzle.
Sum of sequence terms = A088020(5)/2.
152 <= (number of last sequence term) <= 205 (see A087725 and cube archives link for current status). - Hugo Pfoertner, Feb 12 2020

References

Crossrefs

Programs

  • C
    /* See Clausecker link. */
    
  • Fortran
    ! See link in A089473.
    
  • Python
    # alst(), moves(), swap() in A089473
    start, shape = "-123456789ABCDEFGHIJKLMNO", (5, 5)
    alst(start, shape, v=True) # Michael S. Branicky, Dec 31 2020

Extensions

More terms from Tomas Rokicki, Aug 09 2011
a(28)-a(30) from Robert Clausecker, Jan 29 2018
a(31)-a(32) from Robert Clausecker, Sep 14 2020

A107254 a(n) = SF(2n-1)/SF(n-1)^2 where SF = A000178.

Original entry on oeis.org

1, 1, 12, 8640, 870912000, 22122558259200000, 222531556847250309120000000, 1280394777025250130271722799104000000000, 5746332926632566442385615219551212618645504000000000000
Offset: 0

Views

Author

Henry Bottomley, May 14 2005

Keywords

Comments

Inverse product of all matrix elements of n X n Hilbert matrix M(i,j) = 1/(i+j-1) (i,j = 1..n). - Alexander Adamchuk, Apr 12 2006
The n X n matrix with A(i,j) = 1/(i+j-1)! (i,j = 1..n) has determinant (-1)^floor(n/2)/a(n). - Mikhail Lavrov, Nov 01 2022

Examples

			a(3) = 1!*2!*3!*4!*5!/(1!*2!*1!*2!) = 34560/4 = 8640.
n = 2: HilbertMatrix[n,n]
  1/1 1/2
  1/2 1/3
so a(2) = 1 / (1 * 1/2 * 1/2 * 1/3) = 12.
The n X n Hilbert matrix begins:
  1/1 1/2 1/3 1/4  1/5  1/6  1/7  1/8 ...
  1/2 1/3 1/4 1/5  1/6  1/7  1/8  1/9 ...
  1/3 1/4 1/5 1/6  1/7  1/8  1/9 1/10 ...
  1/4 1/5 1/6 1/7  1/8  1/9 1/10 1/11 ...
  1/5 1/6 1/7 1/8  1/9 1/10 1/11 1/12 ...
  1/6 1/7 1/8 1/9 1/10 1/11 1/12 1/13 ...
		

Crossrefs

Programs

  • Magma
    A107254:= func< n | n eq 0 select 1 else (&*[Factorial(n+j)/Factorial(j): j in [0..n-1]]) >;
    [A107254(n): n in [0..12]]; // G. C. Greubel, Apr 21 2021
  • Maple
    a:= n-> mul((n+i)!/i!, i=0..n-1):
    seq(a(n), n=0..10);  # Alois P. Heinz, Jul 23 2012
  • Mathematica
    Table[Product[(i+j-1),{i,1,n},{j,1,n}], {n,1,10}] (* Alexander Adamchuk, Apr 12 2006 *)
    Table[n!*BarnesG[2n+1]/(BarnesG[n+2]*BarnesG[n+1]), {n,0,12}] (* G. C. Greubel, Apr 21 2021 *)
  • Sage
    a = lambda n: prod(rising_factorial(k,n) for k in (1..n))
    print([a(n) for n in (0..10)]) # Peter Luschny, Nov 29 2015
    

Formula

a(n) = n!*(n+1)!*(n+2)!*...*(2n-1)!/(0!*1!*2!*3!*...*(n-1)!) = A000178(2n-1)/A000178(n-1)^2 = A079478(n)/A000984(n) = A079478(n-1)*A009445(n-1) = A107252(n)*A000142(n) = A088020(n)/A039622(n).
a(n) = 1/Product_{j=1..n} ( Product_{i=1..n} 1/(i+j-1) ). - Alexander Adamchuk, Apr 12 2006
a(n) = 2^(n*(n-1)) * A136411(n) for n > 0 . - Robert Coquereaux, Apr 06 2013
a(n) = A136411(n) * A053763(n) for n > 0. [Following remark from Robert Coquereaux] - M. F. Hasler, Apr 06 2013
a(n) ~ A * 2^(2*n^2-1/12) * n^(n^2+1/12) / exp(3*n^2/2+1/12), where A = 1.28242712910062263687534256886979... is the Glaisher-Kinkelin constant (see A074962). - Vaclav Kotesovec, Feb 10 2015
a(n) = Product_{k=1..n} rf(k,n) where rf denotes the rising factorial. - Peter Luschny, Nov 29 2015
a(n) = (n! * G(2*n+1))/(G(n+1)*G(n+2)), where G(n) is the Barnes G - function. - G. C. Greubel, Apr 21 2021

A179268 Product of numbers between and including n and n^2.

Original entry on oeis.org

1, 24, 181440, 3487131648000, 646300418472124416000000, 3099944389915843478899995401256960000000, 844835922269816056767016893501799134566045599137792000000000
Offset: 1

Views

Author

Reinhard Zumkeller, Jul 06 2010

Keywords

Comments

a(n) = Product_{k=n..n^2} k;
a(n) = A088020(n)/A000142(n-1).

Examples

			a(2) = 2*3*4 = 24;
a(3) = 3*4*5*6*7*8*9 = 181440.
		

Crossrefs

Programs

  • Magma
    [Factorial(n^2) / Factorial(n-1): n in [1..10]]; // Vincenzo Librandi, May 31 2011
  • Mathematica
    Table[Times@@Range[n,n^2],{n,10}] (* Harvey P. Dale, Sep 16 2020 *)

Formula

a(n) = (n^2)! / (n-1)!.

Extensions

Definition clarified by Harvey P. Dale, Sep 16 2020

A221976 The number of n X n matrices with zero determinant and with entries a permutation of [1,2,..,n^2].

Original entry on oeis.org

0, 0, 2736, 8290316160
Offset: 1

Views

Author

R. J. Mathar, May 12 2013

Keywords

Comments

This counts a subset of all (n^2)! = A088020(n) matrices which contain elements which are a permutation of [n^2]. The range of determinants is characterized in A085000, and the size of the set of different determinants in A088217.
Because any combination of row and column permutation of matrices with distinct elements generates (n!)^2 = A001044(n) different matrices, and because these restricted permutations leave the (absolute value of) the determinant constant, a(n) is a multiple of A001044(n). This factor does not yet take into account that matrix transpositions also maintain the values of determinants (and which never can be achieved by row or column permutation).

Formula

a(n) = A136609(n)*A001044(n).

A362187 a(n) = (n^2 - n)!.

Original entry on oeis.org

1, 1, 2, 720, 479001600, 2432902008176640000, 265252859812191058636308480000000, 1405006117752879898543142606244511569936384000000000, 710998587804863451854045647463724949736497978881168458687447040000000000000
Offset: 0

Views

Author

Stefano Spezia, Apr 10 2023

Keywords

Comments

The next term has 104 digits.
For n > 0, a(n) is the number of n X n matrices using all the integers from 1 to n^2 and having the main diagonal given.

Crossrefs

Programs

  • Mathematica
    a[n_]:=(n^2-n)!; Array[a,9,0]

Formula

a(n) = (n^2 - n)*a(n-1) for n > 1.
a(n) = A000142(A002378(n-1)) for n > 0.

A364203 Triangle read by rows: T(n, k) is the number of n X n matrices of rank k using all the integers from 1 to n^2.

Original entry on oeis.org

1, 0, 24, 0, 2736, 360144
Offset: 1

Views

Author

Stefano Spezia, Jul 13 2023

Keywords

Examples

			The triangle begins:
  1;
  0,   24;
  0, 2736, 360144;
  ...
		

Crossrefs

Cf. A085000 (maximal determinant), A088020 (row sums), A350565 (minimal permanent), A350566 (maximal permanent), A364206 (right diagonal).
Cf. A364226 (with prime numbers).
Showing 1-10 of 20 results. Next