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A105532 Decimal expansion of arctan 1/5. 3
1, 9, 7, 3, 9, 5, 5, 5, 9, 8, 4, 9, 8, 8, 0, 7, 5, 8, 3, 7, 0, 0, 4, 9, 7, 6, 5, 1, 9, 4, 7, 9, 0, 2, 9, 3, 4, 4, 7, 5, 8, 5, 1, 0, 3, 7, 8, 7, 8, 5, 2, 1, 0, 1, 5, 1, 7, 6, 8, 8, 9, 4, 0, 2, 4, 1, 0, 3, 3, 9, 6, 9, 9, 7, 8, 2, 4, 3, 7, 8, 5, 7, 3, 2, 6, 9, 7, 8, 2, 8, 0, 3, 7, 2, 8, 8, 0, 4, 4, 1, 1, 2, 6, 2, 8 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..104.

Eric Weisstein's World of Mathematics, Machin-Like Formulas

FORMULA

4*arctan(1/5) - A105534 = Pi/4 (Machin's formula).

EXAMPLE

0.197395559849880758370049765194790293447585103787852101517688940241033969...

PROG

(PARI) atan(1/5) \\ Michel Marcus, Sep 24 2014

CROSSREFS

Cf. A003881 (Pi/4), A105534 (arctan 1/239).

Sequence in context: A060388 A081821 A164102 * A111471 A078527 A092425

Adjacent sequences:  A105529 A105530 A105531 * A105533 A105534 A105535

KEYWORD

cons,nonn

AUTHOR

Bryan Jacobs (bryanjj(AT)gmail.com), Apr 12 2005

EXTENSIONS

Corrected position of decimal point in example. - R. J. Mathar, Feb 05 2009

STATUS

approved

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Last modified October 21 22:47 EDT 2019. Contains 328315 sequences. (Running on oeis4.)