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 1-6 of 6 results.

A062990 Eighth column (r=7) of FS(5) staircase array A062985.

Original entry on oeis.org

5, 30, 110, 315, 771, 1688, 3396, 6390, 11385, 19382, 31746, 50297, 77415, 116160, 170408, 245004, 345933, 480510, 657590, 887799, 1183787, 1560504, 2035500, 2629250, 3365505, 4271670, 5379210, 6724085, 8347215
Offset: 0

Views

Author

Wolfdieter Lang, Jul 12 2001

Keywords

Comments

In the Frey-Sellers reference this sequence is called {(n+2) over 7}_{4}, n >= 0.

Crossrefs

Partial sums of A062989.

Programs

  • Maple
    [seq((binomial(n+7,n)-binomial(n+2,n)),n=1..29)]; # Zerinvary Lajos, Jun 23 2006
  • Mathematica
    Table[Binomial[n+7,n]-Binomial[n+2,n],{n,30}] (* or *) LinearRecurrence[ {8,-28,56,-70,56,-28,8,-1},{5,30,110,315,771,1688,3396,6390},30] (* Harvey P. Dale, Jun 09 2016 *)
  • PARI
    { for (n=0, 1000, m=n + 1; a=binomial(m + 7, m) - binomial(m + 2, m); write("b062990.txt", n, " ", a) ) } \\ Harry J. Smith, Aug 15 2009

Formula

a(n) = A062985(n+2, 7) = (n+1)*(n+2)*(n+3)*(n^4 + 29*n^3 + 326*n^2 + 1744*n + 4200)/7!.
G.f.: N(5;1, x)/(1-x)^8 with N(5;1, x)= 5-10*x+10*x^2-5*x^3+x^4 = (1-(1-x)^5)/x polynomial of second row of A062986.
a(n) = binomial(n+7,n) - binomial(n+2,n). - Zerinvary Lajos, Jun 23 2006

Extensions

More terms from Zerinvary Lajos, Jun 23 2006

A062988 a(n) = binomial(n+6,5) - 1.

Original entry on oeis.org

5, 20, 55, 125, 251, 461, 791, 1286, 2001, 3002, 4367, 6187, 8567, 11627, 15503, 20348, 26333, 33648, 42503, 53129, 65779, 80729, 98279, 118754, 142505, 169910, 201375, 237335, 278255, 324631
Offset: 0

Views

Author

Wolfdieter Lang, Jul 12 2001

Keywords

Comments

In the Frey-Sellers reference this sequence is called {(n+2) over 5}_{4}, n >= 0.

Crossrefs

Sixth column (r=5) of FS(5) staircase array A062985.
A column of triangle A014473.

Programs

  • Magma
    [Binomial(n+6,5) -1: n in [0..40]]; // G. C. Greubel, Apr 25 2024
    
  • Maple
    [seq(binomial(n+6,5)-1, n=0..35)]; # Zerinvary Lajos, Nov 25 2006
  • Mathematica
    Binomial[Range[6,45],5] -1 (* G. C. Greubel, Apr 25 2024 *)
  • PARI
    { for (n=0, 1000, write("b062988.txt", n, " ", binomial(n + 6, 5) - 1) ) } \\ Harry J. Smith, Aug 15 2009
    
  • SageMath
    [binomial(n+6,5) -1 for n in range(41)] # G. C. Greubel, Apr 25 2024

Formula

a(n) = A062985(n+2, 5).
a(n) = (n+1)*(n^4 + 19*n^3 + 136*n^2 + 444*n + 600)/5!.
G.f.: N(5;1, x)/(1-x)^6 with N(5;1, x)= 5 - 10*x + 10*x^2 - 5*x^3 + x^4 = (1-(1-x)^5)/x, polynomial of second row of A062986.
E.g.f.: (1/120)*(600 + 1800*x + 1200*x^2 + 300*x^3 + 30*x^4 + x^5)*exp(x). - G. C. Greubel, Apr 25 2024

A062989 a(n) = C(n+6, 6) - n - 1.

Original entry on oeis.org

0, 5, 25, 80, 205, 456, 917, 1708, 2994, 4995, 7997, 12364, 18551, 27118, 38745, 54248, 74596, 100929, 134577, 177080, 230209, 295988, 376717, 474996, 593750, 736255, 906165, 1107540, 1344875, 1623130, 1947761, 2324752, 2760648, 3262589, 3838345, 4496352
Offset: 0

Views

Author

Wolfdieter Lang, Jul 12 2001

Keywords

Comments

In the Frey-Sellers reference this sequence is called {(n+2) over 6}_{4}, n >= 0.

Crossrefs

Seventh column (r=6) of FS(5) staircase array A062985.
Partial sums of A062988.

Programs

  • Mathematica
    Table[Binomial[n+6,6]-n-1,{n,0,40}] (* OR *) LinearRecurrence[ {7,-21,35,-35,21,-7,1},{0,5,25,80,205,456,917},40] (* Harvey P. Dale, Aug 08 2013 *)
  • PARI
    { for (n=0, 1000, write("b062989.txt", n, " ", binomial(n + 6, 6) - n - 1) ) } \\ Harry J. Smith, Aug 15 2009

Formula

a(n) = A062985(n+2, 6) = (n+1)*(n+2)*(n^4 + 24*n^3 + 221*n^2 + 954*n + 1800)/6!.
G.f.: N(5;1, x)/(1-x)^7 with N(5;1, x)= 5-10*x+10*x^2-5*x^3+x^4 = (1-(1-x)^5)/x polynomial of second row of A062986.
a(0)=0, a(1)=5, a(2)=25, a(3)=80, a(4)=205, a(5)=456, a(6)=917, a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7). - Harvey P. Dale, Aug 08 2013
D-finite with recurrence -n*a(n) +(n+6)*a(n-1) +5*n=0. - R. J. Mathar, Nov 22 2024

Extensions

Simpler definition from Zerinvary Lajos, May 08 2006

A062986 Coefficient array for certain polynomials N(5; k,x) (rising powers in x).

Original entry on oeis.org

1, 5, -10, 10, -5, 1, 35, -170, 415, -629, 630, -420, 180, -45, 5, 285, -2315, 9381, -24395, 44625, -59880, 60015, -45040, 25025, -10010, 2730, -455, 35, 2530, -29379, 169405, -633675, 1703700, -3467145, 5497640, -6903325
Offset: 0

Views

Author

Wolfdieter Lang, Jul 12 2001

Keywords

Comments

The g.f. for the sequence of column r=4*k+j, k >= 0, j=1,2,3,4, of the staircase array A062985(n,r) is N(5; k,x)*(x^(k+1))/(1-x)^(4*k+1+j) with N(5; k,x) := sum(a(k,p)*x^p,p=0..4*k).
The m=0 column gives A002294(k+1). The row sums give A000012 (powers of 1) and (unsigned) A062987.
The sequence of step width of this staircase array is [1,4,4,4,...], i.e. the degree of the row polynomials is [0,4,8,12,...]= A008586.

Examples

			{1}; {5,-10,10,-5,1}; {35,-170,415,-629,630,-420,180,-45,5}; ...; N(5; 1,x)= 5-10*x+10*x^2-5*x^3+x^4 = (1-(1-x)^5)/x.
		

Crossrefs

Formula

a(k, p) := [x^p]N(5; k, x) with N(5; k, x)=(N(5; k-1, x)- A002294(k)*(1-x)^(4*k+1))/x, N(5; 0, x) := 1.
a(n, k)= a(n-1, k+1)+((-1)^k)*binomial(4*n+1, k+1)*binomial(5*n+1, n)/(5*n+1) if k=0, .., (4*n-5); a(n, k)= ((-1)^k)*binomial(4*n+1, k+1)*binomial(5*n+1, n)/(5*n+1) if k=(4*n-4), ..., 4*n; else 0.

A334719 a(n) is the total number of down-steps after the final up-step in all 4-Dyck paths of length 5*n (n up-steps and 4*n down-steps).

Original entry on oeis.org

0, 4, 30, 250, 2245, 21221, 208129, 2098565, 21619910, 226593015, 2408424760, 25899375645, 281273231985, 3080585212120, 33986840371400, 377364606387005, 4213620859310140, 47284625533425750, 532996618440511710, 6032169040263819485, 68517222947120776290
Offset: 0

Views

Author

Andrei Asinowski, May 08 2020

Keywords

Comments

A 4-Dyck path is a lattice path with steps U = (1, 4), d = (1, -1) that starts at (0,0), stays (weakly) above the x-axis, and ends at the x-axis.

Examples

			For n = 2, the a(2) = 30 is the total number of down-steps after the last up-step in UddddUdddd, UdddUddddd, UddUdddddd, UdUddddddd, UUdddddddd (thus, 4 + 5 + 6 + 7 + 8).
		

Crossrefs

First order differences of A002294. Cf. A062985.
Cf. A334682 (similar for 3-Dyck paths).

Programs

  • Maple
    b:= proc(x, y) option remember; `if`(x=y, x,
         `if`(y+40, b(x-1, y-1), 0))
        end:
    a:= n-> b(5*n, 0):
    seq(a(n), n=0..20);  # Alois P. Heinz, May 09 2020
    # second Maple program:
    a:= proc(n) option remember; `if`(n<2, 4*n, (5*(5*n-4)*
          (5*n-3)*(5*n-2)*(5*n-1)*n*(2869*n^3+5354*n^2+3239*n+634)*
           a(n-1))/(8*(n-1)*(4*n+3)*(2*n+1)*(4*n+5)*(n+1)*
           (2869*n^3-3253*n^2+1138*n-120)))
        end:
    seq(a(n), n=0..20);  # Alois P. Heinz, May 09 2020
  • Mathematica
    a[n_] := Binomial[5*n + 6, n + 1]/(5*n + 6) - Binomial[5*n + 1, n]/(5*n + 1); Array[a, 21, 0] (* Amiram Eldar, May 13 2020 *)
  • PARI
    a(n) = {binomial(5*(n+1)+1, n+1)/(5*(n+1)+1) - binomial(5*n+1, n)/(5*n+1)} \\ Andrew Howroyd, May 08 2020
    
  • SageMath
    [binomial(5*(n + 1) + 1, n + 1)/(5*(n + 1) + 1) - binomial(5*n + 1, n)/(5*n + 1) for n in srange(30)] # Benjamin Hackl, May 13 2020

Formula

a(n) = binomial(5*(n+1)+1, n+1)/(5*(n+1)+1) - binomial(5*n+1, n)/(5*n+1).
a(n) = A062985(n+1, 4*n-1).
G.f.: ((1 - x)*HypergeometricPFQ([1/5, 2/5, 3/5, 4/5], [1/2, 3/4, 5/4], 3125*x/256) - 1)/x. - Stefano Spezia, Apr 25 2023

A185915 Accumulation array of A185914, by antidiagonals.

Original entry on oeis.org

1, 3, 1, 6, 4, 1, 10, 9, 4, 1, 15, 16, 10, 4, 1, 21, 25, 19, 10, 4, 1, 28, 36, 31, 20, 10, 4, 1, 36, 49, 46, 34, 20, 10, 4, 1, 45, 64, 64, 52, 35, 20, 10, 4, 1, 55, 81, 85, 74, 55, 35, 20, 10, 4, 1, 66, 100, 109, 100, 80, 56, 35, 20, 10, 4, 1, 78, 121, 136, 130, 110, 83, 56, 35, 20, 10, 4, 1, 91, 144, 166, 164, 145, 116, 84, 56, 35, 20, 10, 4, 1, 105, 169, 199, 202, 185, 155, 119, 84, 56, 35, 20, 10, 4, 1
Offset: 1

Views

Author

Clark Kimberling, Feb 06 2011

Keywords

Comments

A member of the accumulation chain ... < A185916 < A185914 < A185915 < ...
(See A144112 for definitions of weight array and accumulation array.)

Examples

			Northwest corner:
1....3....6....10....15....21....28
1....4....9....16....25....36....49
1....4....10...19....31....46....64
1....4....10...20....34....52....74
1....4....10...20....35....55....80
1....4....10...20....35....56....83
row 1: A000217 (triangular numbers)
row 2: A000290 (squares)
row 3: A005448 (centered triangular numbers)
row 4: A005893
row 5: A062985
Limit of rows: A000292 (tetrahedral numbers)
		

Crossrefs

Programs

  • Mathematica
    f[n_, 0] := 0; f[0, k_] := 0; f[n_, k_] := k - n + 1; f[n_, k_] := 0 /; k < n; s[n_, k_] := Sum[f[i, j], {i, 1, n}, {j, 1, k}]; Table[s[n - k + 1, k], {n, 50}, {k, n, 1, -1}] // Flatten

Formula

T(n,k) = C(k+2,3) if k<=n; T(n,k) = k*(k+2-n)/2 if k>n; k>=1, n>=1.
Showing 1-6 of 6 results.