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A152623 Decimal expansion of 3/2. 8
1, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Sum of the inverses of the tetrahedral numbers (A000292). - Michael B. Porter, Nov 27 2017
For any triangle ABC, cos A + cos B + cos C <= 3/2; equality is obtained only when the triangle is equilateral (see the Kiran S. Kedlaya link). - Bernard Schott, Sep 17 2022
LINKS
Kiran S. Kedlaya, A < B, (1999), Problem 6.2, p. 6.
EXAMPLE
1.5000000000000000000000000000000000000000000000000000000000...
PROG
(PARI) 3/2. \\ Charles R Greathouse IV, Jan 10 2022
CROSSREFS
Cf. A000292 (tetrahedral numbers).
Sums of inverses: A002117 (cubes), A175577 (octahedral numbers), A295421 (dodecahedral numbers), A175578 (icosahedral numbers).
Cf. A002194, A020821, A104956 (other trigonometric inequalities).
Sequence in context: A336587 A336586 A241471 * A020761 A341881 A281462
KEYWORD
nonn,cons,easy
AUTHOR
N. J. A. Sloane, Oct 30 2009
STATUS
approved

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Last modified March 29 11:45 EDT 2024. Contains 371278 sequences. (Running on oeis4.)