OFFSET
1,2
COMMENTS
The root mean square RMS(L(0),...,L(n-1)) is firstly an integer for n = 36.
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
FORMULA
n such that (L(0)^2+ L(1)^2+ ... + L(n-1)^2) / n is an integer. L(i) i-th Lucas number.
EXAMPLE
n=10 : (L(0)^2+...+L(9)^2)/10 = 935
MATHEMATICA
With[{nn=1200}, Transpose[Select[Thread[{Range[nn], Accumulate[ LucasL[ Range[0, nn-1]]^2]}], IntegerQ[Last[#]/First[#]]&]][[1]]] (* Harvey P. Dale, Jul 15 2012 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Ctibor O. Zizka, Jul 27 2008
EXTENSIONS
Inserted 1 and extended from 48 on, R. J. Mathar, Aug 04 2008
STATUS
approved