%I A117822
%S A117822 1,1,3,2,8,6,9,21,23,36,50,76,115,179,281,446,712,1142,1837,2961,4779,
%T A117822 7720,12478,20176,32631,52783,85389,138146,223508,361626,585105,946701,
%U A117822 1531775,2478444,4010186,6488596,10498747,16987307,27486017,44473286
%N A117822 a(0) = a(1) = 1; for n >= 2, a(n) = a(n-1) + a(n-2) - (n-1) if that number 
               is positive and not already in the sequence, otherwise a(n) = a(n-1) 
               + a(n-2) + (n-1).
%p A117822 a[0]:=1: a[1]:=1: A:={1}: for n from 2 to 42 do if a[n-1]+a[n-2]-(n-1)>
               0 and member(a[n-1]+a[n-2]-n+1,A)=false then a[n]:=a[n-1]+a[n-2]-n+1: 
               A:=A union {a[n-1]+a[n-2]-n+1} else a[n]:=a[n-1]+a[n-2]+n-1: A:=A 
               union {a[n-1]+a[n-2]+n-1} fi: od: seq(a[n],n=0..42); - Emeric Deutsch 
               (deutsch(AT)duke.poly.edu), Apr 30 2006
%Y A117822 Cf. A079053, A005132, A117821, A117823, A117824.
%Y A117822 Sequence in context: A122358 A122297 A073283 this_sequence A132887 A092174 
               A083514
%Y A117822 Adjacent sequences: A117819 A117820 A117821 this_sequence A117823 A117824 
               A117825
%K A117822 nonn,easy
%O A117822 0,3
%A A117822 N. J. A. Sloane (njas(AT)research.att.com), Apr 30 2006
%E A117822 More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Apr 30 2006