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.

A262809 Number A(n,k) of lattice paths from {n}^k to {0}^k using steps that decrement one or more components by one; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 13, 13, 1, 1, 1, 75, 409, 63, 1, 1, 1, 541, 23917, 16081, 321, 1, 1, 1, 4683, 2244361, 10681263, 699121, 1683, 1, 1, 1, 47293, 308682013, 14638956721, 5552351121, 32193253, 8989, 1, 1, 1, 545835, 58514835289, 35941784497263, 117029959485121, 3147728203035, 1538743249, 48639, 1, 1
Offset: 0

Views

Author

Alois P. Heinz, Oct 02 2015

Keywords

Comments

Also, A(n,k) is the number of alignments for k sequences of length n each (Slowinski 1998).
Row r > 0 is asymptotic to sqrt(r*Pi) * (r^(r-1)/(r-1)!)^n * n^(r*n+1/2) / (2^(r/2) * exp(r*n) * (log(2))^(r*n+1)), or equivalently to sqrt(r) * (r^(r-1)/(r-1)!)^n * (n!)^r / (2^r * (Pi*n)^((r-1)/2) * (log(2))^(r*n+1)). - Vaclav Kotesovec, Mar 23 2016
From Vaclav Kotesovec, Mar 23 2016: (Start)
Column k > 0 is asymptotic to sqrt(c(k)) * d(k)^n / (Pi*n)^((k-1)/2), where c(k) and d(k) are roots of polynomial equations of degree k, independent on n.
---------------------------------------------------
k d(k)
---------------------------------------------------
2 5.8284271247461900976033774484193...
3 56.9476283720414911685286267804411...
4 780.2794068067951456595241495989622...
5 13755.2719024115081712083954421541320...
6 296476.9162644200814909862281498491264...
7 7553550.6198338218721069097516499501996...
8 222082591.6017202421029000117685530884167...
9 7400694480.0494436216324852038000444393262...
10 275651917450.6709238286995776605620357737005...
---------------------------------------------------
d(k) is a root of polynomial:
---------------------------------------------------
k=2, 1 - 6*d + d^2
k=3, -1 + 3*d - 57*d^2 + d^3
k=4, 1 - 12*d - 218*d^2 - 780*d^3 + d^4
k=5, -1 + 5*d - 1260*d^2 - 3740*d^3 - 13755*d^4 + d^5
k=6, 1 - 18*d - 5397*d^2 - 123696*d^3 + 321303*d^4 - 296478*d^5 + d^6
k=7, -1 + 7*d - 24031*d^2 - 374521*d^3 - 24850385*d^4 + 17978709*d^5 - 7553553*d^6 + d^7
k=8, 1 - 24*d - 102692*d^2 - 9298344*d^3 + 536208070*d^4 - 7106080680*d^5 - 1688209700*d^6 - 222082584*d^7 + d^8
(End)
d(k) = (2^(1/k) - 1)^(-k). - David Bevan, Apr 07 2022
d(k) is asymptotic to (k/log(2))^k/sqrt(2). - David Bevan, Apr 07 2022
A(n,k) is the number of binary matrices with k columns and any number of nonzero rows with n ones in every column. - Andrew Howroyd, Jan 23 2020

Examples

			A(2,2) = 13: [(2,2),(1,2),(0,2),(0,1),(0,0)], [(2,2),(1,2),(0,1),(0,0)], [(2,2),(1,2),(1,1),(0,1),(0,0)], [(2,2),(1,2),(1,1),(0,0)], [(2,2),(1,2),(1,1),(1,0),(0,0)], [(2,2),(2,1),(1,1),(0,1),(0,0)], [(2,2),(2,1),(1,1),(0,0)], [(2,2),(2,1),(1,1),(1,0),(0,0)], [(2,2),(2,1),(2,0),(0,1),(0,0)], [(2,2),(2,1),(1,0),(0,0)], [(2,2),(1,1),(0,1),(0,0)], [(2,2),(1,1),(0,0)], [(2,2),(1,1),(1,0),(0,0)].
Square array A(n,k) begins:
  1, 1,    1,        1,             1,                   1, ...
  1, 1,    3,       13,            75,                 541, ...
  1, 1,   13,      409,         23917,             2244361, ...
  1, 1,   63,    16081,      10681263,         14638956721, ...
  1, 1,  321,   699121,    5552351121,     117029959485121, ...
  1, 1, 1683, 32193253, 3147728203035, 1050740615666453461, ...
		

Crossrefs

Columns: A000012 (k=0 and k=1), A001850 (k=2), A126086 (k=3), A263064 (k=4), A263065 (k=5), A263066 (k=6), A263067 (k=7), A263068 (k=8), A263069 (k=9), A263070 (k=10).
Rows: A000012 (n=0), A000670 (n=1), A055203 (n=2), A062208 (n=3), A062205 (n=4), A263061 (n=5), A263062 (n=6), A062204 (n=7), A263063 (n=8), A263071 (n=9), A263072 (n=10).
Main diagonal: A262810.

Programs

  • Maple
    A:= (n, k)-> add(add((-1)^i*binomial(j, i)*
         binomial(j-i, n)^k, i=0..j), j=0..k*n):
    seq(seq(A(n, d-n), n=0..d), d=0..10);
  • Mathematica
    A[, 0] =  1; A[n, k_] := Sum[Sum[(-1)^i*Binomial[j, i]*Binomial[j - i, n]^k, {i, 0, j}], {j, 0, k*n}];
    Table[Table[A[n, d - n], {n, 0, d}], {d, 0, 10}] // Flatten (* Jean-François Alcover, Jul 22 2016, after Alois P. Heinz *)
  • PARI
    T(n,k) = {my(m=n*k); sum(j=0, m, binomial(j,n)^k*sum(i=j, m, (-1)^(i-j)*binomial(i, j)))} \\ Andrew Howroyd, Jan 23 2020

Formula

A(n,k) = Sum_{j=0..k*n} Sum_{i=0..j} (-1)^i*C(j,i)*C(j-i,n)^k.
A(n,k) = Sum_{i >= 0} binomial(i,n)^k/2^(i+1). - Peter Bala, Jan 30 2018
A(n,k) = Sum_{j=0..n*k} binomial(j,n)^k * Sum_{i=j..n*k} (-1)^(i-j) * binomial(i,j). - Andrew Howroyd, Jan 23 2020

A263159 Number A(n,k) of lattice paths starting at {n}^k and ending when k or any component equals 0, using steps that decrement one or more components by one; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 7, 13, 1, 1, 1, 15, 157, 63, 1, 1, 1, 31, 2101, 5419, 321, 1, 1, 1, 63, 32461, 717795, 220561, 1683, 1, 1, 1, 127, 580693, 142090291, 328504401, 9763807, 8989, 1, 1, 1, 255, 11917837, 39991899123, 944362553521, 172924236255, 454635973, 48639, 1, 1
Offset: 0

Views

Author

Alois P. Heinz, Oct 11 2015

Keywords

Examples

			Square array A(n,k) begins:
  1, 1,    1,       1,            1,                1, ...
  1, 1,    3,       7,           15,               31, ...
  1, 1,   13,     157,         2101,            32461, ...
  1, 1,   63,    5419,       717795,        142090291, ...
  1, 1,  321,  220561,    328504401,     944362553521, ...
  1, 1, 1683, 9763807, 172924236255, 7622403922836151, ...
		

Crossrefs

Rows n=0-1 give: A000012, A255047.
Main diagonal gives A263160.

Programs

  • Maple
    s:= proc(n) option remember; `if`(n=0, {[]},
          map(x-> [[x[], 0], [x[], 1]][], s(n-1)))
        end:
    b:= proc(l) option remember; `if`(l=[] or l[1]=0, 1,
           add((p-> `if`(p[1]<0, 0, `if`(p[1]=0, 1, b(p)))
           )(sort(l-x)), x=s(nops(l)) minus {[0$nops(l)]}))
        end:
    A:= (n, k)-> b([n$k]):
    seq(seq(A(n,d-n), n=0..d), d=0..10);
  • Mathematica
    g[k_] := Table[Reverse[IntegerDigits[n, 2]][[;;k]], {n, 2^k+1, 2^(k+1)-1}];
    b[l_] := b[l] = If[l[[1]] == 0, 1, Sum[b[Sort[l - h]], {h, g[k]}]];
    a[n_, k_] := If[n == 0 || k == 0 || k == 1, 1, b[Table[n, {k}]]];
    Table[a[n-k, k], {n, 0, 10}, {k, n, 0, -1}] // Flatten (* Jean-François Alcover, Apr 25 2020, after Alois P. Heinz in A115866 *)

A132595 Number of ways to move a chess queen from the lower left corner to square (n,n), with the queen moving only up, right, or diagonally up-right.

Original entry on oeis.org

1, 3, 22, 188, 1712, 16098, 154352, 1499858, 14717692, 145509218, 1447187732, 14462966928, 145120265472, 1461040916988, 14751839744412, 149316973768398, 1514654852648052, 15393833895932658, 156716528008129892, 1597861126366223768
Offset: 1

Views

Author

Martin J. Erickson (erickson(AT)truman.edu), Nov 14 2007, Jan 28 2009

Keywords

Comments

Main diagonal of the square array given in A132439.
a(n) is the number of Wythoff's Nim games starting with two equal piles of n stones. - Martin J. Erickson (erickson(AT)truman.edu), Dec 05 2008

Examples

			a(2) = 3 since the paths from (1,1) to (2,2) are
(1,1)->(2,1)->(2,2),
(1,1)->(1,2)->(2,2),
(1,1)->(2,2).
		

Crossrefs

Cf. A132439.
Column k=2 of A229345.

Programs

  • Mathematica
    Rest[CoefficientList[Series[(x (x-1)/(3x-2))(1+(1-x)/Sqrt[1-12x+16x^2]),{x,0,20}],x]] (* Harvey P. Dale, Feb 09 2015 *)

Formula

G.f.: (x*(x-1)/(3*x-2))*(1 + (1-x)/sqrt(1 - 12*x + 16*x^2)). a(n) is asymptotic to (5^(3/4)*(sqrt(5)-2)/16)*(6+2*sqrt(5))^n/sqrt(Pi*n).
a(1)=1; a(2)=3; a(3)=22; a(4)=188; a(n) = ((29*n-47)*a(n-1) + (-95*n + 238)*a(n-2) + (116*n - 418)*a(n-3) + (-48*n + 240)*a(n-4))/(2*n-2), n >= 5. - Martin J. Erickson (erickson(AT)truman.edu), Nov 20 2007

A229346 Number of lattice paths from {n}^n to {0}^n using steps that decrement one component or all components by the same positive integer.

Original entry on oeis.org

1, 1, 22, 11380, 991365512, 25162900228200976, 284854886025567226297639952, 2093990992170633308203972573924209991024, 13828588617717374636071022960227309614538766239157199488, 108581118792865622142187514289639080469248439675462122946671780723171080576
Offset: 0

Views

Author

Alois P. Heinz, Sep 24 2013

Keywords

Crossrefs

Main diagonal of A229345.

A229465 Number of lattice paths from {2}^n to {0}^n using steps that decrement one component or all components by the same positive integer.

Original entry on oeis.org

1, 2, 22, 248, 6506, 292442, 19450082, 1781791202, 214899390722, 33007840951682, 6290830043769602, 1456812593474515202, 402910665233497344002, 131173228963457333452802, 49656810289226589524275202, 21628258853895326260083456002, 10739534026001485870629015552002
Offset: 0

Views

Author

Alois P. Heinz, Sep 24 2013

Keywords

Crossrefs

Row n=2 of A229345.

Programs

  • Maple
    a:= proc(n) option remember; `if`(n<5, [1, 2, 22, 248, 6506][n+1],
         ((64481193996*n^5 -656050382562*n^4 +1835465682464*n^3
          -3691825299357*n^2 +10428520019257*n -9978603085078)*a(n-1)
          -(64481193996*n^6 -251022627918*n^5 -4253631972584*n^4
          +29686486719123*n^3 -71916661134305*n^2 +77149141951487*n
          -30090569866279)*a(n-2) +(n-2)*(437268351642*n^5
          -5777340617365*n^4 +26203609431616*n^3 -50411340883791*n^2
          +38226810988733*n -9795152028455)*a(n-3) -(n-2)*(n-3)*
          (170273280324*n^4 -2136687453608*n^3 +8692120865702*n^2
          -11643795721897*n +4287224601259)*a(n-4) -(n-6)*(n-2)*(n-3)*
          (n-4)*(202513877322*n^2-310611483677*n+98391999767)*a(n-5))/
          (32240596998*n^3-328025191281*n^2+768115007074*n-189524735891))
        end:
    seq(a(n), n=0..20);
  • Mathematica
    b[l_] := b[l] = With[{m = Length[l]}, If[m == 0 || l[[m]] == 0, 1, If[m > 1, Sum[b[l - Array[j&, m]], {j, 1, l[[1]]}], 0] + Sum[Sum[b[Sort[ ReplacePart[l, i -> l[[i]] - j]]], {j, 1, l[[i]]}], {i, 1, m}]]];
    a[k_] := b[Array[2&, k]];
    a /@ Range[0, 20] (* Jean-François Alcover, Dec 22 2020, after Alois P. Heinz in A229345 *)

Formula

a(n) ~ sqrt(Pi) * 2^(n+1) * n^(2*n+1/2) / exp(2*n-1). - Vaclav Kotesovec, Jul 16 2014

A229482 Number of lattice paths from {n}^3 to {0}^3 using steps that decrement one component or all components by the same positive integer.

Original entry on oeis.org

1, 7, 248, 11380, 577124, 30970588, 1724240804, 98508192580, 5736813639188, 339068764626556, 20277072462706100, 1224258843324348388, 74504869395134442884, 4564559749008113090620, 281250580532881468554692, 17415330397418786646707236
Offset: 0

Views

Author

Alois P. Heinz, Sep 24 2013

Keywords

Crossrefs

Column k=3 of A229345.

Programs

  • Maple
    b:= proc(l) local m; m:= nops(l); if m=0 or l[m]=0 then 1
          elif m>1 then b(l):= add(add(b(sort(subsop(i=l[i]-j, l))),
          j=1..l[i]), i=1..m)+add(b(map(x->x-j, l)), j=1..l[1]) else 0 fi
        end:
    a:= n-> b([n$3]):
    seq(a(n), n=0..20);
  • Mathematica
    b[l_] := b[l] = With[{m = Length[l]}, If[m == 0 || l[[m]] == 0, 1, If[m > 1, Sum[b[l - Array[j&, m]], {j, 1, l[[1]]}], 0] + Sum[Sum[b[Sort[ ReplacePart[l, i -> l[[i]] - j]]], {j, 1, l[[i]]}], {i, 1, m}]]];
    a[n_] := b[{n, n, n}];
    a /@ Range[0, 20] (* Jean-François Alcover, Dec 22 2020, after Alois P. Heinz *)

Formula

a(n) ~ c*d^n/n, where d = (3*(375+sqrt(17))^(2/3)+156+23*(375+sqrt(17))^(1/3))/(375+sqrt(17))^(1/3) = 66.266905910039023... is the root of the equation -125 + 183*d - 69*d^2 + d^3 = 0 and c = sqrt(-269/225 + 2*sqrt(14561) * cosh(arccosh(60154403/(116488*sqrt(14561)))/3)/225)/Pi = 0.1272434612906147722352211214089... - Vaclav Kotesovec, Sep 25 2013, updated Mar 17 2024
Showing 1-6 of 6 results.