A080137 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=2.

1, 2, 4, 7, 10, 12, 40, 139, 172, 183, 527, 538, 882, 11532, 25022, 25377, 25732, 26087, 286602, 547117, 859806, 1120321, 1433010, 2006214, 3413137, 5132749, 5705953, 10552100, 15971451, 21390802, 26810153

Offset

1,2

Links

Table of n, a(n) for n=1..31.

Prog

(PARI) x=2; 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, ", "))

Crossrefs

Cf. A080136, A080138, A080139, A080140.

Sequence in context: A101359 A007303 A102988 * A102933 A122019 A190279

Adjacent sequences: A080134 A080135 A080136 * A080138 A080139 A080140

Keyword

nonn

Author

Paul D. Hanna, Jan 30 2003

Extensions

Extended with PARI program by Benoit Cloitre, Feb 04 2003

Status

approved