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A309848 Digits of the multiplicative inverse of A309754. 1
1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

-1

LINKS

Table of n, a(n) for n=-1..86.

Wikipedia, p-adic number

FORMULA

By definition, (Sum_{i=-1..n} a(i)*2^(i+1)) * (Sum_{i=0..floor((n+1)/2)} 2^(2*i)/(2*i+1)) == 1 (mod 2^(n+2)).

EXAMPLE

arctanh(2) = ...0111000110010001010010010111010001111010, so 1/arctanh(2) = 010110010000100011000000001011010001010.1.

PROG

(PARI) a(n) = lift(Mod(sum(i=0, (n+1)/2, 2^(2*i)/(2*i+1)), 2^(n+2))^(-1))\2^(n+1)

CROSSREFS

Cf. A309754, A309847.

Sequence in context: A085405 A036988 A108357 * A326822 A088517 A325897

Adjacent sequences:  A309845 A309846 A309847 * A309849 A309850 A309851

KEYWORD

nonn,base

AUTHOR

Jianing Song, Aug 20 2019

STATUS

approved

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Last modified May 21 05:37 EDT 2022. Contains 353889 sequences. (Running on oeis4.)