A065598 a(0)=0, a(1)=1, a(2)=2; for n >= 3, a(n) = 2*a(n-1)*a(n-2) - a(n-3).

0, 1, 2, 4, 15, 118, 3536, 834481, 5901449514, 9849294983780932, 116250234190553238066899615, 2289965696952749203147232235388377288832846, 532418097118181120851300401934424857560888078403591714456723409727648

Offset

0,3

References

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).

Links

Harry J. Smith, Table of n, a(n) for n = 0..17

Maple

A065598 := proc(n) option remember; if n <= 2 then n else 2*A065598(n-1)*A065598(n-2)-A065598(n-3); fi; end;

Mathematica

nxt[{a_, b_, c_}]:={b, c, 2c*b-a}; NestList[nxt, {0, 1, 2}, 12][[All, 1]] (* Harvey P. Dale, Aug 31 2017 *)

Prog

(PARI) { for (n = 0, 17, 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=2))); write("b065598.txt", n, " ", a) ) } \\ Harry J. Smith, Oct 23 2009

Crossrefs

Cf. A065597.

Sequence in context: A228934 A120490 A003514 * A264832 A100528 A132483

Adjacent sequences: A065595 A065596 A065597 * A065599 A065600 A065601

Keyword

nonn,easy

Author

N. J. A. Sloane, Dec 01 2001

Status

approved