

A267182


Row 2 of the square array in A267181.


1



1, 2, 0, 3, 1, 4, 2, 5, 3, 6, 4, 7, 5, 8, 6, 9, 7, 10, 8, 11, 9, 12, 10, 13, 11, 14, 12, 15, 13, 16, 14, 17, 15, 18, 16, 19, 17, 20, 18, 21, 19, 22, 20, 23, 21, 24, 22, 25, 23, 26, 24, 27, 25, 28, 26, 29, 27, 30, 28, 31, 29, 32, 30, 33, 31, 34, 32, 35, 33, 36, 34, 37, 35, 38, 36, 39, 37, 40, 38, 41, 39
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OFFSET

0,2


COMMENTS

From Charlie Neder, Feb 06 2019: (Start)
Colin Barker's conjectures below are true.
Proof: A267181(ka,kb) = A267181(a,b) since both operations preserve the greatest common factor of the two coordinates, so A267181(2k,2) = A267181(k,1) = k for k > 1, the second conjecture. For odd coordinates, we have the forced chain (2k+1,2) > (2,2k+1) > (2,2k1) > ... > (2,1) > (1,2) > (1,1) with k+3 operations, the third conjecture. The rest follow from combining these. (End)


LINKS

Table of n, a(n) for n=0..80.


FORMULA

Conjectures from Colin Barker, Jan 29 2016: (Start)
a(n) = (15*(1)^n+2*n)/4 for n>0.
a(n) = (n2)/2 for n>0 and even.
a(n) = (n+3)/2 for n odd.
a(n) = a(n1)+a(n2)a(n3) for n>3.
G.f.: (1+x3*x^2+2*x^3) / ((1x)^2*(1+x)).
(End) [These are true  see Comments]


CROSSREFS

Cf. A267181.
Sequence in context: A331478 A097065 A084964 * A008720 A340622 A263352
Adjacent sequences: A267179 A267180 A267181 * A267183 A267184 A267185


KEYWORD

nonn


AUTHOR

N. J. A. Sloane, Jan 17 2016


STATUS

approved



