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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A136463 Diagonal of square array A136462: a(n) = C((n+1)*2^(n-1), n) for n>=0.

Original entry on oeis.org

1, 2, 15, 560, 91390, 61124064, 163995687856, 1756185841659392, 75079359427627897200, 12831653340946454374300160, 8777916355714456994772455584000, 24054320541767107204031746600673906688
Offset: 0

Views

Author

Paul D. Hanna, Dec 31 2007

Keywords

Comments

a(n) is divisible by (n+1) for n>=0: a(n)/(n+1) = A136464(n).

Crossrefs

Programs

  • Mathematica
    Table[Binomial[(n+1)2^(n-1),n],{n,0,15}]  (* Harvey P. Dale, Apr 20 2011 *)
  • PARI
    a(n)=binomial((n+1)*2^(n-1),n)
    
  • PARI
    /* a(n) = Coefficient of x^n in series: */
    a(n)=polcoeff(sum(i=0,n,((n+1)/2)^i*log(1+2^i*x +x*O(x^n))^i/i!),n)

Formula

a(n) = [x^n] Sum_{i>=0} ((n+1)/2)^i * log(1 + 2^i*x)^i/i!.
a(n) is found in row n, column 0, of matrix power A136467^(n+1) for n>=0.
a(n) ~ exp(n+1) * 2^(n*(n-1)) / sqrt(2*Pi*n). - Vaclav Kotesovec, Jul 02 2016

A136466 Row 2 of square array A136462: a(n) = C(3*2^(n-1), n) for n>=0.

Original entry on oeis.org

1, 3, 15, 220, 10626, 1712304, 927048304, 1708566412608, 10895665708319184, 244373929798154341120, 19561373281624772727757056, 5658395223117478029148167447552, 5975982733408602667847206514763365888
Offset: 0

Views

Author

Paul D. Hanna, Dec 31 2007

Keywords

Comments

a(n) is found in row n, column 0, of matrix cube A136467^3 for n>=0.

Crossrefs

Cf. A136462; other rows: A136465, A014070, A101346; A136467.

Programs

  • Mathematica
    Table[Binomial[3*2^(n-1),n], {n,0,15}] (* Vaclav Kotesovec, Jul 02 2016 *)
  • PARI
    a(n)=binomial(3*2^(n-1),n)
    
  • PARI
    /* T(n,k) = Coefficient of x^k in series: */ a(n)=polcoeff(sum(i=0,n,(3/2)^i*log(1+2^i*x +x*O(x^n))^i/i!),n)

Formula

a(n) = [x^n] Sum_{i>=0} (3/2)^i * log(1 + 2^i*x)^i/i!.
a(n) ~ 3^n * 2^(n*(n-1)) / n!. - Vaclav Kotesovec, Jul 02 2016

A136501 Triangle, read by rows, where T(n,k) = C(2^k,n-k) for n>=k>=0.

Original entry on oeis.org

1, 1, 1, 0, 2, 1, 0, 1, 4, 1, 0, 0, 6, 8, 1, 0, 0, 4, 28, 16, 1, 0, 0, 1, 56, 120, 32, 1, 0, 0, 0, 70, 560, 496, 64, 1, 0, 0, 0, 56, 1820, 4960, 2016, 128, 1, 0, 0, 0, 28, 4368, 35960, 41664, 8128, 256, 1, 0, 0, 0, 8, 8008, 201376, 635376, 341376, 32640, 512, 1, 0, 0, 0, 1, 11440, 906192, 7624512, 10668000, 2763520, 130816, 1024, 1
Offset: 0

Views

Author

Paul D. Hanna, Jan 01 2008

Keywords

Examples

			Triangle begins:
  1;
  1, 1;
  0, 2, 1;
  0, 1, 4,  1;
  0, 0, 6,  8,     1;
  0, 0, 4, 28,    16,      1;
  0, 0, 1, 56,   120,     32,       1;
  0, 0, 0, 70,   560,    496,      64,        1;
  0, 0, 0, 56,  1820,   4960,    2016,      128,       1;
  0, 0, 0, 28,  4368,  35960,   41664,     8128,     256,      1;
  0, 0, 0,  8,  8008, 201376,  635376,   341376,   32640,    512,    1;
  0, 0, 0,  1, 11440, 906192, 7624512, 10668000, 2763520, 130816, 1024, 1;
		

Crossrefs

Cf. A014070 (central terms), A121688 (row sums), A136502 (matrix inverse).

Programs

  • Magma
    [Binomial(2^k, n-k): k in [0..n], n in [0..12]]; // G. C. Greubel, Mar 15 2021
    
  • Mathematica
    Table[Binomial[2^k, n-k], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Mar 15 2021 *)
  • PARI
    T(n,k)=binomial(2^k,n-k)
    
  • Sage
    flatten([[binomial(2^k, n-k) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Mar 15 2021

A136635 Triangle, read by rows, where T(n,k) = C(n,k) * C(2^k*3^(n-k), n) for n>=k>=0.

Original entry on oeis.org

1, 3, 2, 36, 30, 6, 2925, 2448, 660, 56, 1663740, 1265004, 353430, 42504, 1820, 6774333588, 4368213360, 1114691760, 139915440, 8561520, 201376, 204208594169580, 106458751541142, 23004238451040, 2630276490960
Offset: 0

Views

Author

Vladeta Jovovic and Paul D. Hanna, Jan 15 2008

Keywords

Comments

Main diagonal is A014070(n) = C(2^n,n).
Column 0 is A136393(n) = C(3^n,n).
Row sums form A136637.
Antidiagonal sums form A136638.

Examples

			Triangle begins:
1;
3, 2;
36, 30, 6;
2925, 2448, 660, 56;
1663740, 1265004, 353430, 42504, 1820;
6774333588, 4368213360, 1114691760, 139915440, 8561520, 201376;
204208594169580, 106458751541142, 23004238451040, 2630276490960, 167150463480, 5562289824, 74974368; ...
		

Crossrefs

Cf. A014070 (main diagonal), A136393 (column 0), A136636 (column 1), A136637 (row sums), A136638 (antidiagonal sums).

Programs

  • Mathematica
    Flatten[Table[Binomial[n,k]Binomial[2^k 3^(n-k),n],{n,0,10},{k,0,n}]] (* Harvey P. Dale, Dec 13 2012 *)
  • PARI
    {T(n,k)=binomial(n,k)*binomial(2^k*3^(n-k),n)}
    
  • PARI
    /* Using g.f.: */ {T(n,k)=polcoeff(polcoeff(sum(i=0,n,log(1+3^i*x+2^i*x*y)^i/i!),n,x),k,y)}

Formula

G.f.: A(x,y) = Sum_{n>=0} log(1 + 3^n*x + 2^n*x*y)^n / n!.

A136637 a(n) = Sum_{k=0..n} C(n, k) * C(2^k*3^(n-k), n).

Original entry on oeis.org

1, 5, 72, 6089, 3326498, 12405917044, 336474648380394, 69883583587428350874, 115099747754889610404191160, 1536533057081060754026861201898620, 168527150638482484315370462123098294514192
Offset: 0

Views

Author

Vladeta Jovovic and Paul D. Hanna, Jan 15 2008

Keywords

Comments

Equals row sums of triangle A136635.

Examples

			More generally,
if Sum_{n>=0} log(1 + (p^n + r*q^n)*x )^n / n! = Sum_{n>=0} b(n)*x^n,
then b(n) = Sum_{k=0..n} C(n,k)*r^(n-k) * C(p^k*q^(n-k), n)
(a result due to _Vladeta Jovovic_, Jan 13 2008).
		

Crossrefs

Cf. A136635 (triangle), A014070 (main diagonal), A136393 (column 0), A136636 (column 1), A136638 (antidiagonal sums).

Programs

  • Mathematica
    Table[Sum[Binomial[n,k]*Binomial[2^k*3^(n-k),n], {k, 0, n}], {n, 0, 15}] (* Vaclav Kotesovec, Jul 02 2016 *)
  • PARI
    {a(n)=sum(k=0,n,binomial(n,k)*binomial(2^k*3^(n-k),n))}
    
  • PARI
    /* Using g.f.: */ {a(n)=polcoeff(sum(i=0,n,log(1+(2^i+3^i)*x)^i/i!),n,x)}

Formula

G.f.: A(x) = Sum_{n>=0} log(1 + (2^n + 3^n)*x )^n / n!.
a(n) ~ 3^(n^2) / n!. - Vaclav Kotesovec, Jul 02 2016

A136638 a(n) = Sum_{k=0..[n/2]} C(n-k, k) * C(3^(n-2*k)*2^k, n-k).

Original entry on oeis.org

1, 3, 38, 2955, 1666194, 6775599252, 204212962736426, 47025953519744215608, 84798028785462127288681736, 1219731316443261012339196962784452, 141916030637329352970764084182705691263552
Offset: 0

Views

Author

Vladeta Jovovic and Paul D. Hanna, Jan 15 2008

Keywords

Comments

Equals antidiagonal sums of triangle A136635.

Examples

			More generally, if Sum_{n>=0} log(1 + b*p^n*x + d*q^n*x^2)^n/n! = Sum_{n>=0} a(n)*x^n then a(n) = Sum_{k=0..[n/2]} C(n-k,k)*b^(n-2k)*d^k*C(p^(n-2k)*q^k,n-k).
		

Crossrefs

Cf. A136635 (triangle), A014070 (main diagonal), A136393 (column 0), A136636 (column 1), A136637 (row sums).

Programs

  • Mathematica
    Table[Sum[Binomial[n-k,k]*Binomial[2^k*3^(n-2*k),n-k], {k, 0, Floor[n/2]}], {n, 0, 15}] (* Vaclav Kotesovec, Jul 02 2016 *)
  • PARI
    {a(n)=sum(k=0,n\2,binomial(n-k,k)*binomial(3^(n-2*k)*2^k,n-k))}
    
  • PARI
    /* Using g.f.: */ {a(n)=polcoeff(sum(i=0,n,log(1+3^i*x+2^i*x^2)^i/i!),n,x)}

Formula

G.f.: A(x) = Sum_{n>=0} log(1 + 3^n*x + 2^n*x^2)^n / n!.
a(n) ~ 3^(n^2) / n!. - Vaclav Kotesovec, Jul 02 2016

A166997 G.f.: 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, 12, 56, 5404, 171664, 193729840, 36639136064, 919064160383600, 937227332865348224, 699214061851483321467008, 3577364560049979516493456896, 93123865010226899737836259608990464
Offset: 0

Views

Author

Paul D. Hanna, Nov 22 2009

Keywords

Examples

			G.f: 1 + 12*x^2 + 56*x^3 + 5404*x^4 + 171664*x^5 + 193729840*x^6 +...
which equals 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(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.: [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 of A166998.

A060430 Residue C(2^n,n) mod C(2^n,2).

Original entry on oeis.org

0, 0, 0, 20, 0, 1344, 0, 8160, 0, 349184, 0, 1397760, 0, 0, 306774016, 268431360, 0, 7635468288, 0, 494779760640, 942438088704, 0, 0, 105553109975040, 0, 0, 0, 6004799480791040, 0, 192153583922184192, 0, 576460752169205760, 0, 49191317527028826112, 0
Offset: 1

Views

Author

Labos Elemer, Apr 11 2001

Keywords

Crossrefs

Programs

  • Maple
    for n from 1 to 60 do printf(`%d,`,binomial(2^n, n) mod binomial(2^n,2)) od:
  • Mathematica
    Table[Mod[Binomial[2^n,n],Binomial[2^n,2]],{n,40}] (* Harvey P. Dale, Feb 11 2015 *)
  • Python
    from math import comb
    def A060430(n): return comb(m:=1<Chai Wah Wu, Aug 01 2025

Formula

a(n) = A014070(n) mod A006516(n).

Extensions

More terms from James Sellers, Apr 12 2001
Offset corrected by Harry J. Smith, Jul 05 2009

A060497 a(n) = binomial(2^n, prime(n)).

Original entry on oeis.org

1, 4, 56, 11440, 129024480, 13136858812224, 614965786737727286400, 23665616042362569982121184000, 4818341997044953599090397918009939136000, 150781781287041846344613980638793530715139659227762775040
Offset: 1

Views

Author

Labos Elemer, Apr 11 2001

Keywords

Examples

			n = 4, a(4) = binomial(16,7) = binomial(2^4, p(4)) = 11440.
		

Crossrefs

Programs

  • PARI
    a(n) = { binomial(2^n, prime(n)) } \\ Harry J. Smith, Jul 06 2009

A187083 a(n) = binomial(n^n, n).

Original entry on oeis.org

1, 6, 2925, 174792640, 2475588476563125, 14320984850603177651837856, 50975600425441237253196072020826978589, 155681826868802708662507744652859497547627180714885120, 541851389452483826218851027234763464912884507272826833630475746754951097
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Magma
    [Binomial(n^n, n): n in [1..15]]; // Vincenzo Librandi, Apr 22 2011
  • Mathematica
    Table[Binomial[n^n,n],{n,12}]

Formula

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