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A080033 a(n) is taken to be the smallest positive integer not already present which is consistent with the condition "n is a member of the sequence if and only if a(n) is a multiple of 4". 1

%I

%S 0,2,4,5,8,12,7,16,20,10,24,13,28,32,15,36,40,18,44,21,48,52,23,56,60,

%T 26,64,29,68,72,31,76,80,34,84,37,88,92,39,96,100,42,104,45,108,112,

%U 47,116,120,50,124,53,128,132,55,136,140,58,144,61,148,152,63,156,160,66

%N a(n) is taken to be the smallest positive integer not already present which is consistent with the condition "n is a member of the sequence if and only if a(n) is a multiple of 4".

%H B. Cloitre, N. J. A. Sloane and M. J. Vandermast, <a href="http://www.cs.uwaterloo.ca/journals/JIS/index.html">Numerical analogues of Aronson's sequence</a>, J. Integer Seqs., Vol. 6 (2003), #03.2.2.

%H B. Cloitre, N. J. A. Sloane and M. J. Vandermast, <a href="http://arXiv.org/abs/math.NT/0305308">Numerical analogues of Aronson's sequence</a> (math.NT/0305308)

%F a(8m)=20m, a(8m+1)=8m+2, a(8m+2)=20m+4, a(8m+3)=8m+5, a(8m+4)=20m+8, a(8m+5)=20m+12, a(8m+6)=8m+7, a(8m+7)=20m+16.

%F From _Chai Wah Wu_, Sep 27 2016: (Start)

%F a(n) = 2*a(n-8) - a(n-16) for n > 15.

%F G.f.: x*(4*x^14 + x^13 + 8*x^12 + 12*x^11 + 3*x^10 + 16*x^9 + 6*x^8 + 20*x^7 + 16*x^6 + 7*x^5 + 12*x^4 + 8*x^3 + 5*x^2 + 4*x + 2)/(x^16 - 2*x^8 + 1). (End)

%Y Cf. A079000, A080030, A080032, A079313, A080034.

%K easy,nonn

%O 0,2

%A _N. J. A. Sloane_, Mar 14 2003

%E More terms from _Matthew Vandermast_, Mar 23 2003

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Last modified January 22 12:13 EST 2019. Contains 319363 sequences. (Running on oeis4.)