OFFSET
1,2
FORMULA
For n >= 4, r(n) = -16*(n-1)*(n-2)/((2n-1)*(2n-5)*r(n-1)).
EXAMPLE
4^2 = 16 = 1 + 1/(1/3 +1/(-24/5 + 21/20)).
5^2 = 25 = 1 + 1/(1/3 +1/(-24/5 + 1/(20/21 -25/112))).
MAPLE
L2cfrac := proc(L, targ) local a, i; a := 1/(targ-op(1, L)) ; for i from 2 to nops(L) do a := 1/(a-op(i, L)) ; od: RETURN(a) ; end: A128561 := proc(nmax) local b, n, bnxt; b := [1] ; for n from 2 to nmax do bnxt := L2cfrac(b, n^2) ; b := [op(b), bnxt] ; od: [seq( denom(b[i]), i=1..nops(b))] ; end: A128561(30) ; # R. J. Mathar, Oct 09 2007
CROSSREFS
KEYWORD
frac,nonn
AUTHOR
Leroy Quet, Mar 10 2007
EXTENSIONS
More terms from R. J. Mathar, Oct 09 2007
STATUS
approved