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 11-17 of 17 results.

A174264 Irregular triangle T(n, k) = [x^k]( p(n, x) ), where p(n, x) = (1/x)*(1-x)^(3*n+1)*Sum_{k >= 0} (k*(k+1)*(2*k+1)/6)^n*x^k and p(0, x) = 1, read by rows.

Original entry on oeis.org

1, 1, 1, 1, 18, 42, 18, 1, 1, 115, 1539, 5065, 5065, 1539, 115, 1, 1, 612, 30369, 359056, 1439038, 2255448, 1439038, 359056, 30369, 612, 1, 1, 3109, 487944, 16069256, 177275075, 808273143, 1688579472, 1688579472, 808273143, 177275075, 16069256, 487944, 3109, 1
Offset: 0

Views

Author

Roger L. Bagula, Mar 14 2010

Keywords

Examples

			Irregular triangle begins as:
  1;
  1,   1;
  1,  18,    42,     18,       1;
  1, 115,  1539,   5065,    5065,    1539,     115,      1;
  1, 612, 30369, 359056, 1439038, 2255448, 1439038, 359056, 30369, 612, 1;
		

Crossrefs

Programs

  • Mathematica
    (* First program *)
    p[n_, x_]:= p[n,x]= If[n==0, 1, (1-x)^(3*n+1)*Sum[(k*(k+1)*(2*k+1)/6)^n*x^k, {k, 0, Infinity}]/x];
    Table[CoefficientList[p[n, x], x], {n,0,10}]//Flatten
    (* Second program *)
    T[n_, k_]:= T[n, k]= If[n<2, Binomial[n, k], Sum[(-1)^(k-j+1)*Binomial[3*n+1, k-j +1]*(j*(1+j)*(1+2*j)/6)^n, {j,0,k+1}]];
    Join[{1}, Table[T[n, k], {n,0,10}, {k,0,3*n-2}]//Flatten] (* G. C. Greubel, Mar 25 2022 *)
  • Sage
    @CachedFunction
    def T(n,k):
        if (n<2): return binomial(n,k)
        else: return sum( (-1)^(k-j+1)*binomial(3*n+1, k-j+1)*(j*(1+j)*(1+2*j)/6)^n for j in (0..k+1) )
    [1]+flatten([[T(n,k) for k in (0..3*n-2)] for n in (0..10)]) # G. C. Greubel, Mar 25 2022

Formula

T(n, k) = [x^k]( p(n, x) ), where p(n, x) = (1/x)*(1-x)^(3*n+1)*Sum_{k >= 0} (k*(k+1)*(2*k+1)/6)^n*x^k and p(0, x) = 1.
T(n, k) = Sum_{j=0..k+1} (-1)^(k-j+1)*binomial(3*n+1, k-j+1)*(j*(1+j)*(1+2*j)/6)^n, with T(0, k) = T(1, k) = 1. - G. C. Greubel, Mar 25 2022

Extensions

Edited by G. C. Greubel, Mar 25 2022

A151626 Number of permutations of 2 indistinguishable copies of 1..n with exactly 4 adjacent element pairs in decreasing order.

Original entry on oeis.org

0, 0, 1, 603, 47290, 1822014, 49258935, 1086859301, 21147576440, 379269758400, 6441229796061, 105398150289775, 1680774708581766, 26324724399068626, 407112461900381715, 6239897666881158537, 95036195852840662820, 1440959515956284422196, 21778829725476446172249
Offset: 1

Views

Author

R. H. Hardin, May 29 2009

Keywords

Crossrefs

Column k=4 of A154283.

Programs

  • Magma
    A151626:= func< n | (&+[(-1)^(j+1)*Binomial(2*n+1,5-j)*Binomial(j+1,2)^n: j in [1..5]]) >;
    [A151626(n): n in [1..30]]; // G. C. Greubel, Sep 07 2022
    
  • Mathematica
    With[{B=Binomial}, Table[Sum[(-1)^(j+1)*B[2n+1, 5-j]*B[j+1,2]^n, {j,5}], {n,30}]] (* G. C. Greubel, Sep 07 2022 *)
  • PARI
    a(n) = {15^n - (2*n + 1)*10^n + binomial(2*n+1, 2)*6^n - binomial(2*n+1, 3)*3^n + binomial(2*n+1, 4) } \\ Andrew Howroyd, May 07 2020
    
  • SageMath
    @CachedFunction
    def A151626(n): return sum((-1)^(j+1)*binomial(2*n+1,5-j)*binomial(j+1,2)^n for j in (1..5))
    [A151626(n) for n in (1..30)] # G. C. Greubel, Sep 07 2022

Formula

a(n) = 15^n - (2*n + 1)*10^n + binomial(2*n+1, 2)*6^n - binomial(2*n+1, 3)*3^n + binomial(2*n+1, 4). - Andrew Howroyd, May 07 2020
From G. C. Greubel, Sep 07 2022: (Start)
G.f.: x^3*(1 + 533*x + 7243*x^2 - 223119*x^3 + 878573*x^4 + 5014923*x^5 - 40074183*x^6 + 75062403*x^7 + 19732086*x^8 - 185394420*x^9 + 117543960*x^10 + 43740000*x^11)/((1-x)^5*(1-3*x)^4*(1-6*x)^3*(1-10*x)^2*(1-15*x)).
E.g.f.: exp(15*x) - (1+20*x)*exp(10*x) + 18*x*(1+4*x)*exp(6*x) - 3*x*(1 + 12*x + 12*x^2)*exp(3*x) + (x^2/6)*(15 + 20*x + 4*x^2)*exp(x). (End)

Extensions

Terms a(12) and beyond from Andrew Howroyd, May 07 2020

A151627 Number of permutations of 2 indistinguishable copies of 1..n with exactly 5 adjacent element pairs in decreasing order.

Original entry on oeis.org

0, 0, 0, 72, 27664, 2864328, 163809288, 6727188848, 225167210712, 6590156148912, 175992170793456, 4407169187423736, 105396936343707456, 2437638848729751736, 55010494951127561400, 1219075824289276443744, 26652917330108137129544, 576864003740129587504224
Offset: 1

Views

Author

R. H. Hardin, May 29 2009

Keywords

Crossrefs

Column k=5 of A154283.

Programs

  • Magma
    [(&+[(-1)^j*Binomial(2*n+1, j)*Binomial(7-j, 2)^n: j in [0..5]]): n in [1..30]]; // G. C. Greubel, Sep 07 2022
    
  • Mathematica
    With[{B = Binomial}, Table[Sum[(-1)^j*B[2n+1,j]*B[7-j,2]^n, {j,0,5}], {n, 30}]] (* G. C. Greubel, Sep 07 2022 *)
  • SageMath
    @CachedFunction
    def A151627(n): return sum((-1)^j*binomial(2*n+1, j)*binomial(7-j, 2)^n for j in (0..5))
    [A151627(n) for n in (1..30)] # G. C. Greubel, Sep 07 2022

Formula

From G. C. Greubel, Sep 07 2022: (Start)
a(n) = Sum_{j=0..5} (-1)^j*binomial(2*n+1, j)*binomial(7-j, 2)^n.
G.f.: 8*x^4*(9 + 2324*x - 12462*x^2 - 1858545*x^3 + 34890010*x^4 - 134744022*x^5 - 1875623070*x^6 + 22965673068*x^7 - 95590873845*x^8 + 93562460910*x^9 + 576877450068*x^10 - 2203266593259*x^11 + 2865061552194*x^12 - 347005909980*x^13 - 2472141497400*x^14 + 1471264884000*x^15 + 318864600000*x^16)/((1-x)^6*(1-3*x)^5*(1-6*x)^4*(1-10*x)^3*(1-15*x)^2*(1-21*x)).
E.g.f.: exp(21*x) - (1 + 30*x)*exp(15*x) + 10*x*(3 + 20*x)*exp(10*x) - 6*x*(1 + 24*x + 48*x^2)*exp(6*x) + (9*x^2/2)*(5 + 20*x + 12*x^2)*exp(3*x) - (x^2/30)*(15 + 90*x + 60*x^2 + 8*x^3)*exp(x). (End)

Extensions

Terms a(11) and beyond from Andrew Howroyd, May 06 2020

A151628 Number of permutations of 2 indistinguishable copies of 1..n with exactly 6 adjacent element pairs in decreasing order.

Original entry on oeis.org

0, 0, 0, 1, 5158, 1822014, 242384856, 19323413187, 1130781824398, 54076536713976, 2251621794635088, 84973986733001061, 2985450779006443846, 99474230412387811666, 3185003930126491696920, 98939258210106714816135, 3003063241991742340646382, 89537653738976723063722828
Offset: 1

Views

Author

R. H. Hardin, May 29 2009

Keywords

Crossrefs

Column k=6 of A154283.

Programs

  • Magma
    [(&+[(-1)^j*Binomial(2*n+1, j)*Binomial(8-j, 2)^n: j in [0..6]]): n in [1..30]]; // G. C. Greubel, Sep 07 2022
    
  • Mathematica
    With[{B=Binomial}, Table[Sum[(-1)^j*B[2n+1,j]*B[8-j,2]^n, {j,0,6}], {n, 30}]] (* G. C. Greubel, Sep 07 2022 *)
  • SageMath
    @CachedFunction
    def A151628(n): return sum((-1)^j*binomial(2*n+1, j)*binomial(8-j, 2)^n for j in (0..6))
    [A151628(n) for n in (1..30)] # G. C. Greubel, Sep 07 2022

Formula

From G. C. Greubel, Sep 07 2022: (Start)
a(n) = Sum_{j=0..6} (-1)^j*binomial(2*n+1, j)*binomial(8-j, 2)^n.
G.f.: x^4*(1 + 4948*x + 759393*x^2 - 35443768*x^3 - 508116211*x^4 + 51430255228*x^5 - 1039884450243*x^6 + 5791934217096*x^7 + 99233948186819*x^8 - 2137209451932636*x^9 + 17699047175646675*x^10 - 64844223652304424*x^11 - 67279992193011969*x^12 + 1850800989665593044*x^13 - 8839633922267140593*x^14 + 20366483030687973816*x^15 - 15348635039953199376*x^16 - 39686222209918929480*x^17 + 123668352881463084480*x^18 - 135232901326862200800*x^19 + 35906630373023328000*x^20 + 48364304383014480000*x^21 - 29287301536936800000*x^22 - 4134207084840000000*x^23)/((1-x)^7*(1-3*x)^6*(1-6*x)^5*(1-10*x)^4*(1-15*x)^3*(1-21*x)^2*(1-28*x)).
E.g.f.: exp(28*x) - (1 + 42*x)*exp(21*x) + 45*x*(1 + 10*x)*exp(15*x) - (10/3)*x*(3 + 120*x + 400*x^2)*exp(10*x) + 18*x^2*(5 + 40*x + 48*x^2)*exp(6*x) - (9/10)*x^2*(5 + 90*x + 180*x^2 + 72*x^3)*exp(3*x) + (1/90)*x^3*(105 + 210*x + 84*x^2 + 8*x^3)*exp(x). (End)

Extensions

Terms a(11) and beyond from Andrew Howroyd, May 06 2020

A151629 Number of permutations of 2 indistinguishable copies of 1..n with exactly 7 adjacent element pairs in decreasing order.

Original entry on oeis.org

0, 0, 0, 0, 232, 450048, 163809288, 27306899520, 2898916824320, 230479103253264, 15045786224718576, 853790829031070016, 43726349865720132216, 2073954076439134340896, 92786533933117718314680, 3968339124661862533557120, 163867469809854783921566544
Offset: 1

Views

Author

R. H. Hardin, May 29 2009

Keywords

Crossrefs

Column k=7 of A154283.

Programs

  • Magma
    [(&+[(-1)^j*Binomial(2*n+1, j)*Binomial(9-j, 2)^n: j in [0..7]]): n in [1..30]]; // G. C. Greubel, Sep 08 2022
    
  • Mathematica
    With[{B=Binomial}, Table[Sum[(-1)^j*B[2n+1, j]*B[9-j, 2]^n, {j,0,7}], {n, 30}]] (* G. C. Greubel, Sep 08 2022 *)
  • SageMath
    def A151629(n): return sum((-1)^j*binomial(2*n+1, j)*binomial(9-j, 2)^n for j in (0..7))
    [A151629(n) for n in (1..30)] # G. C. Greubel, Sep 08 2022

Formula

From G. C. Greubel, Sep 07 2022: (Start)
a(n) = Sum_{j=0..7} (-1)^j*binomial(2*n+1, j)*binomial(9-j, 2)^n.
G.f.: 8*x^5*(29 +46686*x +3405558*x^2 -592781020*x^3 +15959334952*x^4 +631633031922*x^5 -49837254287872*x^6 +1300883760100354*x^7 -12994364551718898*x^8 -140176079949572802*x^9 +6513756576348329884*x^10 -101042319163019645166*x^11 +848633388017107293828*x^12 -2913665757033808948194*x^13 -19357175742148303993152*x^14 +332871592406004436180230*x^15 -2265050438781150240585891*x^16 +8844782645551069762176780*x^17 -16577175062101039893470178*x^18 -216035122652452146094327988*x^19 +244246494424905520901547660*x^20 -780226424729404888409973432*x^21 +1345511462530423731597208080*x^22 -1027054667766768116706056160*x^23 -747115159033132605830894400*x^24 +2731966566484322974432464000*x^25 -2760478881311463186555360000*x^26 +892027667079782450985600000*x^27 +450814927116061418400000000*x^28 -303214961231096241600000000*x^29 -30004421338934784000000000*x^30)/( Product_{j=1..8} (1-binomial(j+1,2)*x)^(9-j) ).
E.g.f.: exp(36*x) - (1 + 56*x)*exp(28*x) + 63*x*(1 + 14*x)*exp(21*x) - 15*x*(1 + 60*x + 300*x^2)*exp(15*x) + (250/3)*x^2*(3 + 40*x + 80*x^2)*exp(10*x) - (18/5)*x^2*(5 + 180*x + 720*x^2 + 576*x^3)*exp(6*x) + (9/10)*x^3*(35 + 210*x + 252*x^2 + 72*x^3)*exp(3*x) - (1/630)*x^3*(105 + 840*x + 840*x^2 + 224*x^3 + 16*x^4)*exp(x). (End)

Extensions

Terms a(11) and beyond from Andrew Howroyd, May 06 2020

A151630 Number of permutations of 2 indistinguishable copies of 1..n with exactly 8 adjacent element pairs in decreasing order.

Original entry on oeis.org

0, 0, 0, 0, 1, 37257, 49258935, 19323413187, 3950966047950, 539417838175698, 56160822639510114, 4828612774471173450, 360918591663105680031, 24285778099889122541071, 1507815882167268489272385, 87937588306397361416746005, 4882223035755085016119166100
Offset: 1

Views

Author

R. H. Hardin, May 29 2009

Keywords

Crossrefs

Column k=8 of A154283.

Programs

  • Magma
    [(&+[(-1)^j*Binomial(2*n+1, j)*Binomial(10-j, 2)^n: j in [0..8]]): n in [1..30]]; // G. C. Greubel, Sep 08 2022
    
  • Mathematica
    With[{B=Binomial}, Table[Sum[(-1)^j*B[2n+1,j]*B[10-j,2]^n, {j,0,8}], {n, 30}]] (* G. C. Greubel, Sep 08 2022 *)
  • SageMath
    def A151630(n): return sum((-1)^j*binomial(2*n+1, j)*binomial(10-j, 2)^n for j in (0..8))
    [A151630(n) for n in (1..30)] # G. C. Greubel, Sep 08 2022

Formula

From G. C. Greubel, Sep 08 2022: (Start)
a(n) = Sum_{j=0..8} (-1)^j*binomial(2*n+1, j)*binomial(10-j, 2)^n.
G.f. and e.g.f. are in the file "Generating functions". (End)

Extensions

Terms a(11) and beyond from Andrew Howroyd, May 06 2020

A151631 Number of permutations of 2 indistinguishable copies of 1..n with exactly 9 adjacent element pairs in decreasing order.

Original entry on oeis.org

0, 0, 0, 0, 0, 716, 6030140, 6727188848, 2898916824320, 713977455470200, 121976270685699352, 16151017610840330800, 1776999565259831468176, 170177528415687895764196, 14652450038892876986833140, 1161079239300986084649361440, 86154881092488160155801056400
Offset: 1

Views

Author

R. H. Hardin, May 29 2009

Keywords

Crossrefs

Column k=9 of A154283.

Programs

  • Magma
    [(&+[(-1)^j*Binomial(2*n+1, j)*Binomial(11-j, 2)^n: j in [0..9]]): n in [1..30]]; // G. C. Greubel, Sep 08 2022
    
  • Mathematica
    With[{B=Binomial}, Table[Sum[(-1)^j*B[2n+1, j]*B[11-j, 2]^n, {j,0,9}], {n, 30}]] (* G. C. Greubel, Sep 08 2022 *)
  • SageMath
    def A151631(n): return sum((-1)^j*binomial(2*n+1, j)*binomial(11-j, 2)^n for j in (0..9))
    [A151631(n) for n in (1..30)] # G. C. Greubel, Sep 08 2022

Formula

From G. C. Greubel, Sep 08 2022: (Start)
a(n) = Sum_{j=0..9} (-1)^j*binomial(2*n+1, j)*binomial(11-j, 2)^n.
G.f. and e.g.f. are in the file "Generating functions". (End)

Extensions

Terms a(11) and beyond from Andrew Howroyd, May 06 2020
Previous Showing 11-17 of 17 results.