A276266 a(0) = a(1) = a(2) = 1; for n>2, a(n) = ( a(n-1)*a(n-2) + 1 )^2 / a(n-3).

1, 1, 1, 4, 25, 10201, 16259565169, 1100432328310492581042546436, 31383529740086705883339675381564403354342372463018335778292540655564225

Offset

0,4

Links

Seiichi Manyama, Table of n, a(n) for n = 0..10

Formula

a(n) = A208209(n)^2.

Mathematica

RecurrenceTable[{a[n] == (a[n - 1] a[n - 2] + 1)^2/a[n - 3], a[0] == a[1] == a[2] == 1}, a, {n, 0, 8}] (* Michael De Vlieger, Aug 26 2016 *)

Prog

(Ruby)
def A(m, n)
  a = Array.new(m, 1)
  ary = [1]
  while ary.size < n + 1
    i = a[1..-1].inject(:*) + 1
    i *= i
    break if i % a[0] > 0
    a = *a[1..-1], i / a[0]
    ary << a[0]
  end
  ary
end
def A276266(n)
  A(3, n)
end

Crossrefs

Cf. A081068, A208209.

Sequence in context: A317699 A284106 A063802 * A276268 A350081 A350080

Adjacent sequences: A276263 A276264 A276265 * A276267 A276268 A276269

Keyword

nonn

Author

Seiichi Manyama, Aug 26 2016

Status

approved