A065597 a(0)=0, a(1)=1, a(2)=1; for n >= 3, a(n) = 2*a(n-1)*a(n-2) - a(n-3).

0, 1, 1, 2, 3, 11, 64, 1405, 179829, 505319426, 181742174114903, 183675702207469683831527, 66763242902534057178758511601478574336, 24525571043541618855545577854946122156632189794267317765667241

Offset

0,4

Links

Harry J. Smith, Table of n, a(n) for n = 0..18

F. Axel et al., Vibrational modes in a one dimensional "quasi-alloy": the Morse case, J. de Physique, Colloq. C3, Supp. to No. 7, Vol. 47 (Jul 1986), pp. C3-181-C3-186; see Eq. (10).

Maple

A065597 := proc(n) option remember; if n <= 1 then n else 2*A065597(n-1)*A065597(n-2)-A065597(n-3); fi; end;

Prog

(PARI) { for (n = 0, 18, if (n>2, a=2*a1*a2-a3; a3=a2; a2=a1; a1=a, if (n==0, a=a3=0, if (n==1, a=a2=1, a=a1=1))); write("b065597.txt", n, " ", a) ) } \\ Harry J. Smith, Oct 23 2009

Crossrefs

Cf. A065598.

Sequence in context: A242366 A105217 A066046 * A256394 A219513 A001052

Adjacent sequences: A065594 A065595 A065596 * A065598 A065599 A065600

Keyword

nonn,easy

Author

N. J. A. Sloane, Dec 01 2001

Status

approved