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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A088229 Number of n X n (0,1) matrices with distinct rows.

Original entry on oeis.org

1, 2, 12, 336, 43680, 24165120, 53981544960, 476410007808000, 16517640193528320000, 2252801478912508197273600, 1212983979979000042023881932800, 2587892965783744956308448364029542400, 21943955209199862746410706867184116563968000
Offset: 0

Views

Author

Yuval Dekel (dekelyuval(AT)hotmail.com), Nov 03 2003

Keywords

Crossrefs

Cf. A014070.

Programs

  • Mathematica
    Table[(2^n)!/(2^n - n)!, {n, 1, 15}] (* Vaclav Kotesovec, Jul 02 2016 *)

Formula

a(n) = n! * binomial(2^n, n) = n! * A014070(n).
a(n) ~ 2^(n^2). - Vaclav Kotesovec, Jul 02 2016

Extensions

More terms from Ray Chandler, Nov 06 2003
a(0)=1 prepended and terms a(12) and beyond from Andrew Howroyd, Jan 27 2020

A101346 a(n) = binomial(2^n, n-1).

Original entry on oeis.org

1, 4, 28, 560, 35960, 7624512, 5423611200, 13161885792000, 110859231254749120, 3293259778311548232704, 349928324708588104171703296, 134575849279352109587517966790656, 189165427620415586720308268784807487488, 979739920960712963224129514007339757999308800
Offset: 1

Views

Author

Jorge Coveiro, Dec 25 2004

Keywords

Crossrefs

Cf. A014070. - Paul D. Hanna, Jun 21 2009

Programs

  • Maple
    seq(binomial(2^n,n-1),n=1..20);
  • Mathematica
    Table[Binomial[2^n,n-1], {n,1,15}] (* Vaclav Kotesovec, Jul 02 2016 *)
  • PARI
    a(n)=binomial(2^n,n-1) \\ Paul D. Hanna, Jun 21 2009
    
  • PARI
    a(n)=polcoeff(x*sum(k=0,n,2^k*log(1+2^k*x+x*O(x^n))^k/k!),n) \\ Paul D. Hanna, Jun 21 2009

Formula

G.f.: A(x) = x*Sum_{n>=0} 2^n*log(1+2^n*x)^n/n!. - Paul D. Hanna, Jun 21 2009
a(n) ~ 2^(n*(n-1)) / (n-1)!. - Vaclav Kotesovec, Jul 02 2016

Extensions

Terms a(13) and beyond from Andrew Howroyd, Feb 12 2020

A136507 a(n) = Sum_{k=0..n} binomial(2^(n-k) + k, n-k).

Original entry on oeis.org

1, 3, 10, 71, 1925, 203904, 75214965, 94608676477, 409763735870986, 6208539881584781823, 334272186911271376874561, 64832512634295914941490910360, 45811927207957062190019240099653265
Offset: 0

Views

Author

Paul D. Hanna, Jan 01 2008

Keywords

Crossrefs

Cf. A014070 (C(2^n, n)), A136505 (C(2^n+1, n)), A136506 (C(2^n+2, n)).

Programs

  • Magma
    [(&+[Binomial(2^k +n-k, k): k in [0..n]]): n in [0..20]]; // G. C. Greubel, Mar 14 2021
  • Maple
    A136507:= n-> add(binomial(2^k +n-k, k), k=0..n); seq(A136507(n), n=0..20); # G. C. Greubel, Mar 14 2021
  • Mathematica
    Table[Sum[Binomial[2^(n-k)+k,n-k],{k,0,n}],{n,0,20}] (* Harvey P. Dale, Mar 08 2015 *)
  • PARI
    {a(n)=sum(k=0,n,binomial(2^(n-k)+k,n-k))}
    for(n=0,16, print1(a(n),", "))
    
  • PARI
    /* a(n) = coefficient of x^n in o.g.f. series: */
    {a(n)=polcoeff(sum(i=0,n,1/(1-x-2^i*x^2 +x*O(x^n))*log(1+2^i*x +x*O(x^n))^i/i!),n)}
    for(n=0,16, print1(a(n),", "))
    
  • Sage
    [sum(binomial(2^k +n-k, k) for k in (0..n)) for n in (0..20)] # G. C. Greubel, Mar 14 2021
    

Formula

G.f.: A(x) = Sum_{n>=0} (1 - x - 2^n*x^2)^(-1) * log(1 + 2^n*x)^n/n!.
a(n) ~ 2^(n^2) / n!. - Vaclav Kotesovec, Jul 02 2016
a(n) = Sum_{k=0..n} A136555(n-k+1, k). - G. C. Greubel, Mar 14 2021

A360693 Number T(n,k) of sets of n words of length n over binary alphabet where the first letter occurs k times; triangle T(n,k), n>=0, n-signum(n)<=k<=n*(n-1)+signum(n), read by rows.

Original entry on oeis.org

1, 1, 1, 2, 2, 2, 3, 10, 15, 15, 10, 3, 4, 37, 108, 228, 336, 394, 336, 228, 108, 37, 4, 5, 101, 600, 2150, 5645, 11680, 19752, 27820, 32935, 32935, 27820, 19752, 11680, 5645, 2150, 600, 101, 5, 6, 226, 2490, 14745, 61770, 200529, 535674, 1211485, 2368200
Offset: 0

Views

Author

Alois P. Heinz, Feb 16 2023

Keywords

Comments

T(n,k) is defined for all n >= 0 and k >= 0. The triangle contains only the positive elements.

Examples

			T(2,3) = 2: {aa,ab}, {aa,ba}.
T(3,3) = 10: {aab,abb,bbb}, {aab,bab,bbb}, {aab,bba,bbb}, {aba,abb,bbb}, {aba,bab,bbb}, {aba,bba,bbb}, {abb,baa,bbb}, {abb,bab,bba}, {baa,bab,bbb}, {baa,bba,bbb}.
T(4,3) = 4: {abbb,babb,bbab,bbbb}, {abbb,babb,bbba,bbbb}, {abbb,bbab,bbba,bbbb}, {babb,bbab,bbba,bbbb}.
Triangle T(n,k) begins:
  1;
  1, 1;
  .  2, 2,  2;
  .  .  3, 10, 15,  15,  10,    3;
  .  .  .   4, 37, 108, 228,  336,  394,   336,   228,   108,    37,     4;
  .  .  .   .   5, 101, 600, 2150, 5645, 11680, 19752, 27820, 32935, 32935, ...;
  ...
		

Crossrefs

Row sums give A014070.
Column sums give A360695.
Main diagonal T(n,n) gives A154323(n-1) for n>=1.
T(n,n-1) gives A000027(n) for n>=1.
T(2n,2n^2) gives A360702.
Cf. A000290, A057427, A220886 (similar triangle for multisets).

Programs

  • Maple
    g:= proc(n, i, j) option remember; expand(`if`(j=0, 1, `if`(i<0, 0, add(
          g(n, i-1, j-k)*x^(i*k)*binomial(binomial(n, i), k), k=0..j))))
        end:
    T:= n-> (p-> seq(coeff(p, x, i), i=n-signum(n)..n*(n-1)+signum(n)))(g(n$3)):
    seq(T(n), n=0..6);
  • Mathematica
    g[n_, i_, j_] := g[n, i, j] = Expand[If[j == 0, 1, If[i < 0, 0, Sum[g[n, i - 1, j - k]*x^(i*k)*Binomial[Binomial[n, i], k], {k, 0, j}]]]];
    T[n_] := Table[Coefficient[#, x, i], {i, n - Sign[n], n(n - 1) + Sign[n]}]&[g[n, n, n]];
    Table[T[n], {n, 0, 6}] // Flatten (* Jean-François Alcover, May 26 2023, after Alois P. Heinz *)

Formula

T(n,k) = T(n,n^2-k).

A093048 a(n) = n minus exponent of 2 in n, with a(0) = 0.

Original entry on oeis.org

0, 1, 1, 3, 2, 5, 5, 7, 5, 9, 9, 11, 10, 13, 13, 15, 12, 17, 17, 19, 18, 21, 21, 23, 21, 25, 25, 27, 26, 29, 29, 31, 27, 33, 33, 35, 34, 37, 37, 39, 37, 41, 41, 43, 42, 45, 45, 47, 44, 49, 49, 51, 50, 53, 53, 55, 53, 57, 57, 59, 58, 61, 61, 63, 58, 65, 65, 67, 66, 69
Offset: 0

Views

Author

Ralf Stephan, Mar 16 2004

Keywords

Examples

			G.f. = x + x^2 + 3*x^3 + 2*x^4 +  5*x^5 + 5*x^6 + 7*x^7 + 5*x^8 + 9*x^9 + ... - _Michael Somos_, Jan 25 2020
		

Crossrefs

a(n) = n - A007814(n) = A093049(n) + 1, n > 0.
a(n) is the exponent of 2 in A002689(n-1), A014070(n), A060690(n), A075101(n).
See also A084623.

Programs

  • Maple
    A093048 := proc(n)
        n-A007814(n) ;
    end proc: # R. J. Mathar, Jul 24 2014
  • Mathematica
    a[ n_] := If[ n == 0, n - IntegerExponent[n, 2]]; (* Michael Somos, Jan 25 2020 *)
  • PARI
    a(n) = if(n<1, 0, if(n%2==0, a(n/2) + n/2 - 1, n))
    
  • PARI
    a(n) = n - valuation(n, 2) \\ Jianing Song, Oct 24 2018
    
  • Python
    def A093048(n): return n-(~n& n-1).bit_length() if n else 0 # Chai Wah Wu, Jul 07 2022

Formula

Recurrence: a(2n) = a(n) + n - 1, a(2n+1) = 2n + 1.
G.f.: Sum_{k>=0} (t*(t^3 + t^2 + 1)/(1 - t^2)^2), with t = x^2^k.
a(n) = Sum_{k=1..n} sign(n mod 2^k). - Wesley Ivan Hurt, May 09 2021

A136470 Triangle T, read by rows, where column 0 of T^m = {C(m*2^n, n), n>=0} for all m.

Original entry on oeis.org

1, 2, 1, 6, 8, 1, 56, 128, 32, 1, 1820, 6048, 2176, 128, 1, 201376, 912128, 419328, 34816, 512, 1, 74974368, 449708544, 249300992, 26198016, 548864, 2048, 1, 94525795200, 739136655360, 477013868544, 59943682048, 1604059136, 8650752, 8192, 1, 409663695276000, 4132411271661568, 3028532448264192, 439222754869248, 14159357935616, 98723430400, 136839168, 32768, 1, 6208116950265950720, 80121787455478857728, 65415571433959456768, 10679727629898088448, 399723620798038016, 3391703461396480, 6141702569984, 2172649472, 131072, 1
Offset: 0

Views

Author

Paul D. Hanna, Dec 31 2007

Keywords

Comments

Column 0 of T^(n+1) = row 2n+1 of square array A136462 defined by: A136462(n,k) = C((n+1)*2^(k-1), k); T^n denotes the n-th matrix power of this triangle T = A136470.

Examples

			Triangle T begins:
1;
2, 1;
6, 8, 1;
56, 128, 32, 1;
1820, 6048, 2176, 128, 1;
201376, 912128, 419328, 34816, 512, 1;
74974368, 449708544, 249300992, 26198016, 548864, 2048, 1;
94525795200, 739136655360, 477013868544, 59943682048, 1604059136, 8650752, 8192, 1;
409663695276000, 4132411271661568, 3028532448264192, 439222754869248, 14159357935616, 98723430400, 136839168, 32768, 1; ...
Column 0 of T^m is given by: [T^m](n,0) = C(m*2^n, n) for n>=0.
		

Crossrefs

Cf. columns: A014070, A136471, A136472; A136467 (matrix square-root); A136462.

Programs

  • PARI
    {T(n,k)=local(M=matrix(n+1,n+1,r,c,binomial(r*2^(c-2),c-1)),P); P=matrix(n+1,n+1,r,c,binomial((r+1)*2^(c-2),c-1));((P~*M~^-1)^2)[n+1,k+1]}
    for(n=0, 10, for(k=0, n, print1(T(n, k), ", ")); print(""))

Formula

Equals the matrix square of triangle A136467.
Diagonals: T(n+1,n) = 2*4^n; T(n+2,n) = 2*8^n*(2^(n+2) + n-1).

A136636 a(n) = n * C(2*3^(n-1), n) for n>=1.

Original entry on oeis.org

2, 30, 2448, 1265004, 4368213360, 106458751541142, 19173684851378353296, 26413015283743616538733008, 285290979402099025600644272168880, 24601033850235942230699563821233785600080
Offset: 1

Views

Author

Vladeta Jovovic and Paul D. Hanna, Jan 15 2008

Keywords

Comments

Equals column 1 of triangle A136635.

Crossrefs

Cf. A136635 (triangle), A014070 (main diagonal), A136393 (column 0), A136637 (row sums), A136638 (antidiagonal sums).

Programs

  • Maple
    A136636:=n->n*binomial(2*3^(n-1), n); seq(A136636(n), n=1..10); # Wesley Ivan Hurt, Apr 29 2014
  • Mathematica
    Table[n*Binomial[2*3^(n - 1), n], {n, 10}] (* Wesley Ivan Hurt, Apr 29 2014 *)
  • PARI
    {a(n)=n*binomial(2*3^(n-1),n)}

Formula

a(n) ~ 2^n * 3^(n*(n-1)) / (n-1)!. - Vaclav Kotesovec, Jul 02 2016

A166995 G.f.: C(x) = Sum_{n>=0} log(1 - 2^(2n)*x)^(2n)/(2n)!, a power series in x with integer coefficients.

Original entry on oeis.org

1, 0, 8, 32, 2848, 87808, 97425920, 18364346368, 459757145081856, 468713931103109120, 349620381018764380930048, 1788712998645738038832398336, 46562065744123901943395531497144320
Offset: 0

Views

Author

Paul D. Hanna, Nov 22 2009

Keywords

Examples

			G.f: C(x) = 1 + 8*x^2 + 32*x^3 + 2848*x^4 + 87808*x^5 + 97425920*x^6 +...
The g.f. of A166996 is S(x):
S(x) = Sum_{n>=0} -log(1 - 2^(2n+1)*x)^(2n+1)/(2n+1)!
S(x) = 2*x + 2*x^2 + 88*x^3 + 1028*x^4 + 289184*x^5 + 22451552*x^6 +...
where C(x) + S(x) = Sum_{n>=0} C(2^n + n - 1, n)*x^n ... (cf. A060690)
and C(x) - S(x) = Sum_{n>=0} C(2^n, n)*(-x)^n ... (cf. A014070).
Related expansions:
C(x) + S(x) = 1 + 2*x + 10*x^2 + 120*x^3 + 3876*x^4 + 376992*x^5 +...
C(x) - S(x) = 1 - 2*x + 6*x^2 - 56*x^3 + 1820*x^4 - 201376*x^5 +...
		

Crossrefs

Programs

  • Mathematica
    Table[(1/2)*(Binomial[2^n + n - 1, n ] + (-1)^n *Binomial[2^n, n]), {n, 0, 10}] (* G. C. Greubel, May 30 2016 *)
  • PARI
    {a(n)=polcoeff(sum(k=0,n,log(1-2^(2*k)*x +x*O(x^n))^(2*k)/(2*k)!),n)}
    
  • PARI
    {a(n)=(binomial(2^n + n-1, n) + (-1)^n*binomial(2^n, n))/2} \\ Paul D. Hanna, Nov 24 2009

Formula

a(n) = ( C(2^n + n-1, n) + (-1)^n*C(2^n, n) )/2. - Paul D. Hanna, Nov 24 2009

A166996 G.f.: S(x) = Sum_{n>=0} -log(1 - 2^(2n+1)*x)^(2n+1)/(2n+1)!, a power series in x with integer coefficients.

Original entry on oeis.org

2, 2, 88, 1028, 289184, 22451552, 112890141568, 50093449805856, 6676830881369059840, 15354513520142235310592, 66620888067382334066280699904, 750203718611121304644623635491840
Offset: 1

Views

Author

Paul D. Hanna, Nov 22 2009

Keywords

Examples

			G.f.: S(x) = 2*x + 2*x^2 + 88*x^3 + 1028*x^4 + 289184*x^5 + 22451552*x^6 + ...
The g.f. of A166995 is C(x):
C(x) = Sum_{n>=0} log(1 - 2^(2n)*x)^(2n)/(2n)!.
C(x) = 1 + 8*x^2 + 32*x^3 + 2848*x^4 + 87808*x^5 + 97425920*x^6 + ...
where C(x) + S(x) = Sum_{n>=0} C(2^n + n - 1, n)*x^n ... (cf. A060690)
and C(x) - S(x) = Sum_{n>=0} C(2^n, n)*(-x)^n ... (cf. A014070).
Related expansions:
C(x) + S(x) = 1 + 2*x + 10*x^2 + 120*x^3 + 3876*x^4 + 376992*x^5 + ...
C(x) - S(x) = 1 - 2*x + 6*x^2 - 56*x^3 + 1820*x^4 - 201376*x^5 + ...
		

Crossrefs

Programs

  • Mathematica
    Table[(1/2)*(Binomial[2^n + n - 1, n ] - (-1)^n *Binomial[2^n, n]), {n, 50}] (* G. C. Greubel, May 30 2016 *)
  • PARI
    {a(n)=polcoeff(-sum(k=0,n,log(1-2^(2*k+1)*x +x*O(x^n))^(2*k+1)/(2*k+1)!),n)}
    
  • PARI
    {a(n)=(binomial(2^n + n-1, n) - (-1)^n*binomial(2^n, n))/2} \\ Paul D. Hanna, Nov 24 2009

Formula

a(n) = (binomial(2^n + n-1, n) - (-1)^n*binomial(2^n, n) )/2. [Paul D. Hanna, Nov 24 2009]

A166998 G.f.: sqrt(C(x)^2 - S(x)^2) where C(x) = Sum_{n>=0} log(1 - 2^(2n)*x)^(2n)/(2n)! and S(x) = Sum_{n>=0} -log(1 - 2^(2n+1)*x)^(2n+1)/(2n+1)! are the g.f.s of A166995 and A166996, respectively.

Original entry on oeis.org

1, 0, 6, 28, 2684, 85664, 96848424, 18318978896, 459531493100736, 468613553577122688, 349607028167776160389536, 1788682277200384090414421312, 46561932503015793339090359576558496
Offset: 0

Views

Author

Paul D. Hanna, Nov 22 2009

Keywords

Examples

			G.f: 1 + 6*x^2 + 28*x^3 + 2684*x^4 + 85664*x^5 + 96848424*x^6 +...
which equals sqrt( C(x)^2 - S(x)^2 ) where
C(x) = 1 + 8*x^2 + 32*x^3 + 2848*x^4 + 87808*x^5 + 97425920*x^6 +...
S(x) = 2*x + 2*x^2 + 88*x^3 + 1028*x^4 + 289184*x^5 + 22451552*x^6 +...
Related expansions:
C(x) + S(x) = 1 + 2*x + 10*x^2 + 120*x^3 + 3876*x^4 + 376992*x^5 +...
C(x) - S(x) = 1 - 2*x + 6*x^2 - 56*x^3 + 1820*x^4 - 201376*x^5 +...
		

Crossrefs

Programs

  • PARI
    {a(n)=polcoeff(sqrt(sum(k=0,n,log(1-2^(2*k)*x +x*O(x^n))^(2*k)/(2*k)!)^2-sum(k=0,n,log(1-2^(2*k+1)*x +x*O(x^n))^(2*k+1)/(2*k+1)!)^2),n)}

Formula

G.f.: sqrt([C(x)+S(x)]*[C(x)-S(x)]) where C(x) + S(x) = g.f. of A060690 and C(-x) - S(-x) = g.f. of A014070.
Self-convolution yields A166998.
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