A014005 Pisot sequence E(9,19), a(n)=[ a(n-1)^2/a(n-2)+1/2 ].

9, 19, 40, 84, 176, 369, 774, 1624, 3407, 7148, 14997, 31465, 66016, 138507, 290599, 609700, 1279199, 2683861, 5630953, 11814185, 24787095, 52005287, 109111208, 228923950, 480300565, 1007708598, 2114252392, 4435868847, 9306803910, 19526411174, 40967956027

Offset

0,1

Links

Colin Barker, Table of n, a(n) for n = 0..1000

D. W. Boyd, Some integer sequences related to the Pisot sequences, Acta Arithmetica, 34 (1979), 295-305.

D. W. Boyd, Linear recurrence relations for some generalized Pisot sequences, Advances in Number Theory ( Kingston ON, 1991) 333-340, Oxford Sci. Publ., Oxford Univ. Press, New York, 1993.

Formula

Known not to satisfy any linear recurrence.

Prog

(PARI) pisotE(nmax, a1, a2) = {
  a=vector(nmax); a[1]=a1; a[2]=a2;
  for(n=3, nmax, a[n] = floor(a[n-1]^2/a[n-2]+1/2));
  a
}
pisotE(50, 9, 19) \\ Colin Barker, Jul 28 2016

Crossrefs

Sequence in context: A039299 A211114 A159697 * A286624 A058510 A043122

Adjacent sequences: A014002 A014003 A014004 * A014006 A014007 A014008

Keyword

nonn

Author

Simon Plouffe

Status

approved