

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



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, 26, 64, 29, 68, 72, 31, 76, 80, 34, 84, 37, 88, 92, 39, 96, 100, 42, 104, 45, 108, 112, 47, 116, 120, 50, 124, 53, 128, 132, 55, 136, 140, 58, 144, 61, 148, 152, 63, 156, 160, 66
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OFFSET

0,2


LINKS

Table of n, a(n) for n=0..65.
B. Cloitre, N. J. A. Sloane and M. J. Vandermast, Numerical analogues of Aronson's sequence, J. Integer Seqs., Vol. 6 (2003), #03.2.2.
B. Cloitre, N. J. A. Sloane and M. J. Vandermast, Numerical analogues of Aronson's sequence (math.NT/0305308)


FORMULA

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.
From Chai Wah Wu, Sep 27 2016: (Start)
a(n) = 2*a(n8)  a(n16) for n > 15.
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)


CROSSREFS

Cf. A079000, A080030, A080032, A079313, A080034.
Sequence in context: A295032 A280017 A080136 * A007379 A080588 A032850
Adjacent sequences: A080030 A080031 A080032 * A080034 A080035 A080036


KEYWORD

easy,nonn


AUTHOR

N. J. A. Sloane, Mar 14 2003


EXTENSIONS

More terms from Matthew Vandermast, Mar 23 2003


STATUS

approved



