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A080138 Least positive integer multiples of angle x such that their direction cosines form a unit vector: sum(k>0, cos(a(k)*x)^2)=1, where a(1)=1 and x=3. 5

%I

%S 1,11,12,33,100,122,144,233,344,477,588,832,943,1187,2008,15853,16563,

%T 17273,121621,191068,260515,503757,573204,955340,1337476,1719612,

%U 2101748,3317603,4464011,4846147,5228283,5610419,10647634,16066985

%N Least positive integer multiples of angle x such that their direction cosines form a unit vector: sum(k>0, cos(a(k)*x)^2)=1, where a(1)=1 and x=3.

%o (PARI) x=3; z=cos(x)^2; a=1; for(n=1,35,b=a+1; while(z+cos(b*x)^2>1,b++); z=z+cos(b*x)^2; a=b; print1(b,","))

%Y Cf. A080136, A080137, A080139, A080140.

%K nonn

%O 1,2

%A _Paul D. Hanna_, Jan 30 2003

%E Corrected and extended with PARI program by _Benoit Cloitre_, Feb 04 2003

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Last modified May 26 01:32 EDT 2022. Contains 354073 sequences. (Running on oeis4.)