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A046698 a(0) = 0, a(1) = 1, a(n) = a(a(n-1)) + a(a(n-2)) if n > 1. 17

%I

%S 0,1,1,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,

%T 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,

%U 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2

%N a(0) = 0, a(1) = 1, a(n) = a(a(n-1)) + a(a(n-2)) if n > 1.

%C Partial sums are A004275. Binomial transform is A048492, starting with 0. - _Paul Barry_, Feb 28 2003

%D Sequence proposed by Reg Allenby.

%D O. Deveci, Y. Akuzum, E. Karaduman, O. Erdag, The Cyclic Groups via Bezout Matrices, Journal of Mathematics Research, Vol. 7, No. 2, 2015, pp. 34-41.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Fibonaccin-StepNumber.html">Fibonacci n-Step Number</a>

%F G.f.: x*(1+x^2)/(1-x). - _Paul Barry_, Feb 28 2003

%F a(n) = 2*((n+2) mod (n+1))-(C(n^2,n+2) mod 2)-(C((n+1)^2,n+3) mod 2). - _Paolo P. Lava_, Sep 03 2007

%p P:=proc(n) local a,i; for i from 0 by 1 to n do a:=2*((i+2) mod (i+1))-(binomial((i)^2,i+2) mod 2)-(binomial((i+1)^2,i+3) mod 2); print(a); od; end: P(100); # _Paolo P. Lava_, Sep 03 2007

%o (PARI) a(n)=(n>0)+(n>2)

%K nonn,easy

%O 0,4

%A _N. J. A. Sloane_, _R. K. Guy_

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Last modified November 14 22:32 EST 2019. Contains 329134 sequences. (Running on oeis4.)