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A073448 Decimal expansion of sec(1). 12
1, 8, 5, 0, 8, 1, 5, 7, 1, 7, 6, 8, 0, 9, 2, 5, 6, 1, 7, 9, 1, 1, 7, 5, 3, 2, 4, 1, 3, 9, 8, 6, 5, 0, 1, 9, 3, 4, 7, 0, 3, 9, 6, 6, 5, 5, 0, 9, 4, 0, 0, 9, 2, 9, 8, 8, 3, 5, 1, 5, 8, 2, 7, 7, 8, 5, 8, 8, 1, 5, 4, 1, 1, 2, 6, 1, 5, 9, 6, 7, 0, 5, 9, 2, 1, 8, 4, 1, 4, 1, 3, 2, 8, 7, 3, 0, 6, 6, 7, 1, 1, 4, 9, 1, 0 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
By the Lindemann-Weierstrass theorem, this constant is transcendental. - Charles R Greathouse IV, May 13 2019
LINKS
Mohammad K. Azarian, Forty-Five Nested Equilateral Triangles and cosecant of 1 degree, Problem 813, College Mathematics Journal, Vol. 36, No. 5, November 2005, pp. 413-414.
Mohammad K. Azarian, Solution of Forty-Five Nested Equilateral Triangles and cosecant of 1 degree, Problem 813, College Mathematics Journal, Vol. 37, No. 5, November 2006, pp. 394-395.
FORMULA
Equals Sum_{k>=0} (-1)^k * E(2*k) / (2*k)!, where E(k) is the k-th Euler number (A122045). - Amiram Eldar, May 15 2021
EXAMPLE
1.85081571768092561791175324139...
MATHEMATICA
RealDigits[Sec[1], 10, 120][[1]] (* Harvey P. Dale, Mar 13 2013 *)
PROG
(PARI) 1/cos(1)
CROSSREFS
Cf. A049470 (cos(1)=1/A073448), A049469 (sin(1)), A049471 (tan(1)), A073447 (csc(1)), A073449 (cot(1)), A122045.
Sequence in context: A230162 A197841 A143347 * A073745 A086730 A249449
KEYWORD
cons,nonn
AUTHOR
Rick L. Shepherd, Aug 01 2002
STATUS
approved

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Last modified June 20 16:59 EDT 2024. Contains 373530 sequences. (Running on oeis4.)