OFFSET
1,5
FORMULA
|a(n)| ~ c^(phi^n), where phi = A001622 = (1+sqrt(5))/2 is the golden ratio and c = 1.097478514051533426... . - Vaclav Kotesovec, Jan 26 2016
MATHEMATICA
a[1] = 1; a[2] = 1; a[n_] := a[n] = -a[n - 1] - a[n - 2] + a[n - 1]*a[n - 2]; Table[a[n], {n, 20}]
nxt[{a_, b_}]:={b, a*b-a-b}; NestList[nxt, {1, 1}, 20][[All, 1]] (* Harvey P. Dale, Nov 29 2022 *)
CROSSREFS
KEYWORD
sign
AUTHOR
José María Grau Ribas, Jan 24 2016
STATUS
approved