A123395 Values X satisfying the equation 7(X-Y)^4-16XY=0, where X>=Y.

0, 27, 6144, 1549125, 393289536, 99891091323, 25371897661440, 6444361377895077, 1636842406341623424, 415751526662194438875, 105599250926807591663616, 26821793983834918021139973

Offset

0,2

Comments

To find Y values: b(n) = c(n)*(-1+d(n)) which gives: 0, 21, 6048, 1547595, 393265152, 99890702709, ...

Links

G. C. Greubel, Table of n, a(n) for n = 0..395

Formula

a(n) = c(n)*(1+d(n)) with c(0) = 0, c(1) = 3 and c(n) = 16*c(n-1) - c(n-2), d(0) = 1, d(1) = 8 and d(n) = 16*d(n-1) - d(n-2).

From Max Alekseyev, Nov 13 2009: (Start)

For n>=4, a(n) = 270*a(n-1) - 4066*a(n-2) + 270*a(n-3) - a(n-4).

O.g.f.: 3*x*(9*x^2 -382*x +9)/((x^2 -16*x +1)*(x^2 -254*x +1)). (End)

Prog

(PARI) x='x+O('x^50); concat([0], Vec(3*x*(9*x^2 -382*x +9)/((x^2 -16*x +1)*(x^2 -254*x +1)))) \\ G. C. Greubel, Oct 13 2017

Crossrefs

Sequence in context: A046367 A059795 A211928 * A051680 A013828 A343922

Adjacent sequences: A123392 A123393 A123394 * A123396 A123397 A123398

Keyword

nonn

Author

Mohamed Bouhamida, Oct 14 2006

Extensions

More terms from Max Alekseyev, Nov 13 2009

Status

approved