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A096824
a(n) = n for n <= 2; for n > 2, a(n) = 2a(n-1) - a(n - floor(1/2 + sqrt(2(n-1)))).
3
0, 1, 2, 3, 4, 6, 9, 14, 24, 42, 75, 136, 258, 492, 942, 1809, 3482, 6828, 13398, 26304, 51666, 101523, 199564, 395646, 784464, 1555530, 3084756, 6117846, 12134169, 24068774, 47937984, 95480322, 190176180, 378796830, 754508904, 1502899962
OFFSET
0,3
LINKS
MATHEMATICA
a[n_] := a[n] = If[n < 3, a[n] = n, 2a[n - 1] - a[n - Floor[1/2 + Sqrt[2(n - 1)]]]]; Table[ a[n], {n, 0, 35}] (* Robert G. Wilson v, Aug 20 2004 *)
PROG
(PARI) {m=36; v=vector(m+1); for(n=0, m, if(n<=2, a=n, k=n-floor(1/2+sqrt(2*(n-1))); a=2*v[n]-v[k+1]); v[n+1]=a; print1(a, ", "))} \\ Klaus Brockhaus, Aug 20 2004
(Haskell)
a096824 n = a096824_list !! n
a096824_list = 0 : 1 : 2 : zipWith (-)
(map (* 2) $ drop 2 a096824_list) (map a096824 $ tail a122797_list)
-- Reinhard Zumkeller, Feb 12 2012
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Aug 17 2004
EXTENSIONS
More terms from Klaus Brockhaus and Robert G. Wilson v, Aug 20 2004
STATUS
approved