OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
FORMULA
For n>=17, a(n) = a(n-2) + a(n-4) + 1 (conjectured). If true then for m>5, a(2*m+1) = 4*F(m) + 25*F(m+1) + 1 and a(2*m+2) = 8*F(m) + 30*F(m+1) + 1 with F(n) = A000045(n). - Ralf Stephan, Nov 15 2010
MATHEMATICA
nxt[{a_, b_}]:={b, Floor[Sqrt[a^2+b^2]]}; Transpose[NestList[nxt, {10, 30}, 60]][[1]] (* Harvey P. Dale, Jun 18 2013 *)
PROG
(Magma)
A104863:= func< n| n lt 3 select 10*(2*n-1) else Floor(Sqrt(Self(n-1)^2 +Self(n-2)^2)) >;
[A104863(n): n in [1..60]]; // G. C. Greubel, Jun 27 2021
(Sage)
@CachedFunction
def a(n): return 10*(2*n-1) if (n<3) else floor(sqrt(a(n-1)^2 + a(n-2)^2))
[a(n) for n in (1..60)] # G. C. Greubel, Jun 27 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Mar 28 2005
STATUS
approved