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A278066 Relative of Hofstadter Q-sequence: a(1) = 5, a(2) = 2; thereafter a(n) = a(n-a(n-1)) + a(n-a(n-2)). 14

%I #5 Nov 14 2016 10:32:33

%S 5,2,5,2,5,7,2,12,2,12,2,12,7,4,14,14,10,14,7,14,6,26,10,4,20,33,2,33,

%T 2,33,2,33,2,38,2,38,2,38,7,4,40,40,10,40,7,14,6,78,10,4,46,85,2,85,2,

%U 85,2,85,2,85,2,85,2,85,2,85,2,85,2,85,2,85,2,85,2,85,2

%N Relative of Hofstadter Q-sequence: a(1) = 5, a(2) = 2; thereafter a(n) = a(n-a(n-1)) + a(n-a(n-2)).

%C In calculating terms of this sequence, use the convention that a(n)=0 for n<=0.

%C Most terms in this sequence alternate between 2 and a term of A275163. These runs are separated by 18 other terms, and each run is approximately twice as long as the previous.

%H Nathan Fox, <a href="/A278066/b278066.txt">Table of n, a(n) for n = 1..10000</a>

%H N. Fox, <a href="https://vimeo.com/191094180">Hofstadter-like Sequences over Nonstandard Integers"</a>, Talk given at the Rutgers Experimental Mathematics Seminar, November 10 2016.

%F a(1) = 5, a(2) = 2, a(3) = 5, a(4) = 2, a(5) = 5, a(6) = 7, a(7) = 2; thereafter, for k>=0,

%F a(A275163(k)+1)=A275163(k)+5

%F a(A275163(k)+2)=2

%F a(A275163(k)+3)=A275163(k)+5

%F a(A275163(k)+4)=2

%F a(A275163(k)+5)=A275163(k)+5

%F a(A275163(k)+6)=7

%F a(A275163(k)+7)=4

%F a(A275163(k)+8)=A275163(k)+7

%F a(A275163(k)+9)=A275163(k)+7

%F a(A275163(k)+10)=10

%F a(A275163(k)+11)=A275163(k)+7

%F a(A275163(k)+12)=7

%F a(A275163(k)+13)=14

%F a(A275163(k)+14)=6

%F a(A275163(k)+15)=2*A275163(k)+12

%F a(A275163(k)+16)=10

%F a(A275163(k)+17)=4

%F a(A275163(k)+18)=A275163(k)+13

%F a(A275163(k)+i)=A275163(k+1), i odd, 19<=i<A275163(k+1)-A275163(k)

%F a(A275163(k)+i)=2, i odd, 20<=i<=A275163(k+1)-A275163(k).

%Y Cf. A005185, A275163, A278067, A278068.

%K nonn

%O 1,1

%A _Nathan Fox_, Nov 13 2016

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