A152623 Decimal expansion of 3/2.

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

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

Table of n, a(n) for n=1..99.

Kiran S. Kedlaya, A < B, (1999), Problem 6.2, p. 6.

Index entries for linear recurrences with constant coefficients, signature (1).

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

Adjacent sequences: A152620 A152621 A152622 * A152624 A152625 A152626

Keyword

nonn,cons,easy

Author

N. J. A. Sloane, Oct 30 2009

Status

approved