A268587 -id:A268587 - cp's OEIS frontend

A268598 Expansion of x^5(4 - 5x)/(1 - 2*x)^4.

0, 0, 0, 0, 0, 4, 27, 120, 440, 1440, 4368, 12544, 34560, 92160, 239360, 608256, 1517568, 3727360, 9031680, 21626880, 51249152, 120324096, 280166400, 647495680, 1486356480, 3391094784, 7693402112, 17364418560, 39007027200, 87241523200, 194330492928

Offset: 0

Ran Pan, Feb 08 2016

a(n) is the number of North-East lattice paths from (0,0) to (n,n) that have exactly two east steps below y = x - 1 and exactly one east step above y = x+1. Details can be found in Section 4.1 in Pan and Remmel's link.

Colin Barker, Table of n, a(n) for n = 0..1000
Ran Pan, Jeffrey B. Remmel, Paired patterns in lattice paths, arXiv:1601.07988 [math.CO], 2016.
Index entries for linear recurrences with constant coefficients, signature (8,-24,32,-16).

Cf. A268462, A268586, A268587.

concat(vector(5), Vec((4-5*x)*x^5/(1-2*x)^4 + O(x^40))) \\ Michel Marcus, Feb 08 2016

G.f.: x^5*(4 - 5*x)/(1 - 2*x)^4.
From Colin Barker, Feb 08 2016: (Start)
a(n) = 2^(n-7)*(n-4)*(n-3)*(n+3) for n>2.
a(n) = 8*a(n-1)-24*a(n-2)+32*a(n-3)-16*a(n-4) for n>3. (End)

A268599 Expansion of 2x^6(4-10x+7x^2)/(1-2*x)^5.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 8, 60, 294, 1180, 4200, 13776, 42560, 125568, 357120, 985600, 2652672, 6988800, 18077696, 46018560, 115507200, 286326784, 701890560, 1703411712, 4096655360, 9771417600, 23132110848, 54384394240, 127049662464, 295069286400, 681574400000

Offset: 0

Ran Pan, Feb 08 2016

a(n) is the number of North-East lattice paths from (0,0) to (n,n) that have exactly two east steps below y = x - 1 and exactly two easts step above y = x + 1. Details can be found in Section 4.1 in Pan and Remmel's link.

Colin Barker, Table of n, a(n) for n = 0..1000
Ran Pan, Jeffrey B. Remmel, Paired patterns in lattice paths, arXiv:1601.07988 [math.CO], 2016.
Index entries for linear recurrences with constant coefficients, signature (10,-40,80,-80,32).

Cf. A268462, A268586, A268587, A268598.

CoefficientList[Series[2 x^6 (4 - 10 x + 7 x^2)/(1 - 2 x)^5, {x, 0, 30}], x] (* Michael De Vlieger, Feb 08 2016 *)

concat(vector(6), Vec(2*x^6*(4-10*x+7*x^2)/(1-2*x)^5 + O(x^100))) \\ Colin Barker, Feb 08 2016

G.f.: 2*x^6*(4-10*x+7*x^2)/(1-2*x)^5.

a(n) = 2^(n-10)*(n-5)*(n-4)*(n^2+3*n+10) for n>3. - Colin Barker, Feb 08 2016

A268600 Expansion of 1/(2f(x)) + 1/(4 - 2g(x)), where f(x) = sqrt(1 - 4x) and g(x) = sqrt(1 + 4x).

Original entry on oeis.org

1, 2, 4, 12, 36, 132, 456, 1752, 6340, 24660, 91224, 356776, 1337896, 5250728, 19877904, 78209712, 298176516, 1175437428, 4505865144, 17789574792, 68490100536, 270739425528, 1046041377264, 4139198745552, 16039426479336, 63522770785032, 246761907761776, 977995685565072, 3807202080396240, 15098691607042000, 58884954519908896

Offset: 0

Ran Pan, Feb 08 2016

nonn

a(n) is the number of North-East lattice paths from (0,0) to (n,n) in which the total number of east steps below y = x - 1 or above y = x + 1 is even. Details can be found in Section 4.1 in Pan and Remmel's link.

			G.f. = 1 + 2*x + 4*x^2 + 12*x^3 + 36*x^4 + 132*x^5 + 456*x^6 + ... - _Michael Somos_, May 16 2022

Ran Pan and Jeffrey B. Remmel, Paired patterns in lattice paths, arXiv:1601.07988 [math.CO], 2016.

Cf. A268462, A268586, A268587, A268598, A268599.

Cf. A000984, A126984.

CoefficientList[ Series[1/(2 Sqrt[1 - 4x]) + 1/(4 - 2 Sqrt[1 + 4x]), {x, 0, 25}], x] (* Robert G. Wilson v, Nov 24 2016 *)

my(x = 'x + O('x^40)); Vec(1/(2*sqrt(1-4*x)) + 1/(4 - 2*sqrt(1+4*x))) \\ Michel Marcus, Feb 11 2016

a(n) = binomial(2*n,n) - A268601(n).
G.f.: 1/(2*f(x)) + 1/(4 - 2*g(x)), where f(x) = sqrt(1 - 4*x) and g(x) = sqrt(1 + 4*x).
Conjecture D-finite with recurrence: -3*n*(n-1)*a(n) +8*(n-1)*(5*n-12)*a(n-1) +4*(-28*n+73)*a(n-2) -160*(2*n-5)*(2*n-7)*a(n-3) +192*(2*n-5)*(2*n-7)*a(n-4)=0. - R. J. Mathar, Jan 25 2020
a(n) = (-1)^n*A126984(n) + A268601(n). - Michael Somos, May 16 2022

A268601 Expansion of 1/(2f(x)) - 1/(4 - 2g(x)), where f(x) = sqrt(1 - 4x) and g(x) = sqrt(1 + 4x).

Original entry on oeis.org

0, 0, 2, 8, 34, 120, 468, 1680, 6530, 23960, 93532, 348656, 1366260, 5149872, 20238696, 76907808, 302903874, 1158168792, 4569270156, 17555689008, 69356428284, 267518448912, 1058057586456, 4094231982048, 16208177203764, 62887835652720, 249156625186328, 968943740083040, 3841488520364200, 14968574892499040, 59379627044952528

Offset: 0

Ran Pan, Feb 08 2016

nonn

a(n) is the number of North-East lattice paths from (0,0) to (n,n) in which the total number of east steps below y = x - 1 or above y = x + 1 is odd. Details can be found in Section 4.1 in Pan and Remmel's link.

Ran Pan and Jeffrey B. Remmel, Paired patterns in lattice paths, arXiv:1601.07988 [math.CO], 2016.

Cf. A268462, A268586, A268587, A268598, A268599.

x = 'x + O('x^30); concat(vector(2), Vec(1/(2*sqrt(1-4*x)) - 1/(4 - 2*sqrt(1+4*x)))) \\ Michel Marcus, Feb 11 2016

a(n) = binomial(2*n,n) - A268600(n).
G.f.: 1/(2*f(x)) - 1/(4 - 2*g(x)), where f(x) = sqrt(1 - 4*x) and g(x) = sqrt(1 + 4*x).
Conjecture D-finite with recurrence: 3*n*(n-1)*a(n) -8*(n-1)*(5*n-12)*a(n-1) +4*(28*n-73)*a(n-2) +160*(2*n-5)*(2*n-7)*a(n-3) -192*(2*n-5)*(2*n-7)*a(n-4)=0. - R. J. Mathar, Jan 25 2020

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A268598 Expansion of x^5*(4 - 5*x)/(1 - 2*x)^4.

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A268599 Expansion of 2*x^6*(4-10*x+7*x^2)/(1-2*x)^5.

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A268600 Expansion of 1/(2*f(x)) + 1/(4 - 2*g(x)), where f(x) = sqrt(1 - 4*x) and g(x) = sqrt(1 + 4*x).

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A268601 Expansion of 1/(2*f(x)) - 1/(4 - 2*g(x)), where f(x) = sqrt(1 - 4*x) and g(x) = sqrt(1 + 4*x).

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A268598 Expansion of x^5(4 - 5x)/(1 - 2*x)^4.

A268599 Expansion of 2x^6(4-10x+7x^2)/(1-2*x)^5.

A268600 Expansion of 1/(2f(x)) + 1/(4 - 2g(x)), where f(x) = sqrt(1 - 4x) and g(x) = sqrt(1 + 4x).

A268601 Expansion of 1/(2f(x)) - 1/(4 - 2g(x)), where f(x) = sqrt(1 - 4x) and g(x) = sqrt(1 + 4x).