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.

A175939 Number of lattice paths from (0,0) to (n,n) using steps S={(k,0),(0,k),(r,r)|k>0,0

Original entry on oeis.org

1, 2, 10, 62, 448, 3495, 28640, 242946, 2114829, 18783658, 169546150, 1550728135, 14340859992, 133867779775, 1259689173181, 11936488052113, 113799596287017, 1090803942244627, 10505978544362607, 101623141479156708, 986801698075230291
Offset: 0

Views

Author

Eric Werley, Dec 06 2010

Keywords

References

  • J. P. S. Kung and A. de Mier, Catalan lattice paths with rook, bishop and spider steps, Journal of Combinatorial Theory, Series A 120 (2013) 379-389. - From N. J. A. Sloane, Dec 27 2012

Crossrefs

Programs

  • Mathematica
    Flatten[{1,RecurrenceTable[{(n+2)*a[n]+(3*n+7)*a[n+1]-(5*n+24)*a[n+2]-(19*n+90)*a[n+3]+(n+3)*a[n+4]+(21*n+116)*a[n+5]-2*(n+7)*a[n+6]==0, a[1]==2, a[2]==10, a[3]==62, a[4]==448, a[5]==3495, a[6]==28640},a,{n,20}]}] (* Vaclav Kotesovec, Sep 07 2012 *)

Formula

a(n) ~ b*c^n/n^(3/2), where c = 10.458904071481665... is the root of the equation x^4-10*x^3-5*x^2+2*x+1=0 and b = sqrt(2*(1-5*c-15*c^2+2*c^3) /c^3)*(-5 - 4*c + 21*c^2 + 27*c^3) / (44*c^3*sqrt(Pi)) = 0.3791408579... - Vaclav Kotesovec, Aug 10 2013
G.f.: ((x^4+2*x^3-5*x^2-10*x+1)^(1/2)-x^2-3*x-1)/(2*x*(x-1)*(x+2)^2). - Mark van Hoeij, Apr 16 2013

Extensions

Minor edits Vaclav Kotesovec, Mar 31 2014

A175935 Number of lattice paths from (0,0) to (n,n) using steps S={(k,0),(0,k),(r,r)|0

Original entry on oeis.org

1, 2, 10, 55, 351, 2401, 17248, 128221, 978082, 7612155, 60204488, 482481220, 3909460725, 31974923487, 263623879118, 2188682538746, 18282238300443, 153537981720402, 1295640515428649, 10980400434511117, 93418283866708579
Offset: 0

Views

Author

Eric Werley, Dec 06 2010

Keywords

Crossrefs

A175936 Number of lattice walks from (0,0) to (n,n) using steps S={(k,0),(0,k),(r,r)|0

Original entry on oeis.org

1, 2, 10, 62, 433, 3262, 25784, 210892, 1769793, 15152252, 131826824, 1162114368, 10357863128, 93183955872, 845064072102, 7717150002692, 70903816529979, 654967192303546, 6079243786794502, 56668633625876866, 530291242720187193
Offset: 0

Views

Author

Eric Werley, Dec 06 2010

Keywords

Crossrefs

A175937 Number of lattice paths from (0,0) to (n,n) using steps S={(k,0),(0,k),(r,r)|0

Original entry on oeis.org

1, 2, 10, 62, 448, 3464, 28111, 236022, 2033145, 17867442, 159558635, 1443747386, 13207922431, 121962046864, 1135246916024, 10640772522150, 100346005711723, 951400275042466, 9063703952844960, 86718277215053218, 832901296331740527
Offset: 0

Views

Author

Eric Werley, Dec 06 2010

Keywords

Crossrefs

A307733 a(0) = a(1) = 1; a(n) = a(n-1) + a(n-2) + Sum_{k=0..n-1} a(k) * a(n-k-1).

Original entry on oeis.org

1, 1, 4, 14, 54, 220, 934, 4090, 18344, 83850, 389214, 1829736, 8693962, 41685714, 201442188, 980091814, 4797070022, 23603701828, 116688837886, 579312087802, 2887020896016, 14437318756818, 72424982972862, 364366674463824, 1837954750285458
Offset: 0

Views

Author

Ilya Gutkovskiy, Jul 05 2020

Keywords

Crossrefs

Programs

  • Mathematica
    a[0] = a[1] = 1; a[n_] := a[n] = a[n - 1] + a[n - 2] + Sum[a[k] a[n - k - 1], {k, 0, n - 1}]; Table[a[n], {n, 0, 24}]
    nmax = 24; CoefficientList[Series[(1 - x - x^2 - Sqrt[1 - 6 x + 3 x^2 + 2 x^3 + x^4])/(2 x), {x, 0, nmax}], x]

Formula

G.f. A(x) satisfies: A(x) = (1 - x + x*A(x)^2) / (1 - x - x^2).
G.f.: (1 - x - x^2 - sqrt(1 - 6*x + 3*x^2 + 2*x^3 + x^4)) / (2*x).

A346506 G.f. A(x) satisfies: A(x) = (1 + x * A(x)^2) / (1 - x + x^2).

Original entry on oeis.org

1, 2, 5, 17, 66, 274, 1190, 5341, 24577, 115326, 549747, 2654739, 12959468, 63848307, 317064921, 1585380283, 7975134892, 40332823042, 204947059412, 1045859173864, 5357606584326, 27540884494209, 142023060613755, 734506610474205, 3808771672620618, 19798640525731461, 103149287155802941
Offset: 0

Views

Author

Ilya Gutkovskiy, Jul 21 2021

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 26; A[] = 0; Do[A[x] = (1 + x A[x]^2)/(1 - x + x^2) + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]
    a[0] = 1; a[1] = 2; a[n_] := a[n] = 2 a[n - 1] + a[n - 2] + Sum[a[k] a[n - k - 1], {k, 2, n - 1}]; Table[a[n], {n, 0, 26}]

Formula

a(0) = 1, a(1) = 2; a(n) = 2 * a(n-1) + a(n-2) + Sum_{k=2..n-1} a(k) * a(n-k-1).
From Nikolaos Pantelidis, Jan 08 2023 (Start)
G.f.: 1/G(0), where G(k) = 1-(2*x-x^2)/(1-x/G(k+1)) (continued fraction).
G.f.: (1-x+x^2-sqrt(x^4-2*x^3+3*x^2-6*x+1))/(2*x).
(End)
Showing 1-6 of 6 results.