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A080140 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=(2/3). 5
1, 2, 3, 7, 12, 16, 21, 26, 40, 73, 106, 139, 172, 205, 238, 271, 417, 516, 549, 893, 1237, 1581, 1958, 2302, 3023, 3367, 4088, 10822, 20407, 25732, 26797, 78261, 182254, 338776, 442769, 599291, 859806, 1120321, 1380836, 2318903, 4559545, 6279157 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..42.

PROG

(PARI) x=(2/3); z=cos(x)^2; a=1; for(n=1, 45, b=a+1; while(z+cos(b*x)^2>1, b++); z=z+cos (b*x)^2; a=b; print1(b, ", "))

CROSSREFS

Cf. A080136, A080137, A080138, A080139.

Sequence in context: A330593 A275374 A168249 * A019568 A128458 A066733

Adjacent sequences:  A080137 A080138 A080139 * A080141 A080142 A080143

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Jan 30 2003

EXTENSIONS

Extended with PARI program by Benoit Cloitre, Feb 04 2003

STATUS

approved

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Last modified May 30 05:35 EDT 2020. Contains 334712 sequences. (Running on oeis4.)