A306554 Expansion of the 10-adic cube root of 1/13, that is, the 10-adic integer solution to x^3 = 1/13.
3, 5, 6, 4, 1, 9, 3, 2, 8, 7, 4, 0, 8, 3, 6, 5, 7, 7, 0, 9, 8, 2, 7, 5, 1, 4, 8, 0, 9, 5, 1, 6, 0, 6, 2, 1, 3, 2, 2, 6, 4, 2, 7, 0, 6, 8, 6, 1, 3, 3, 2, 2, 0, 0, 1, 5, 6, 7, 9, 6, 2, 7, 8, 4, 2, 6, 3, 6, 3, 0, 1, 0, 4, 5, 5, 6, 6, 1, 3, 5, 4, 3, 3, 3, 1, 7, 0
Offset: 1
Examples
3^3 == 7 == 1/13 (mod 10). 53^3 == 77 == 1/13 (mod 100). 653^3 == 77 == 1/13 (mod 1000). 4653^3 == 3077 == 1/13 (mod 10000). ... ...047823914653^3 = ...923076923077 = 1 + (...999999999999)*(12/13) = 1 - 12/13 = 1/13.
Links
- Robert Israel, Table of n, a(n) for n = 1..10000
Crossrefs
10-adic cube root of p/q:
q=13: A306555 (p=-1), this sequence (p=1).
Programs
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Maple
op([1,3],padic:-rootp(13*x^3-1,10,100)); # Robert Israel, Mar 24 2019
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PARI
seq(n)={Vecrev(digits(lift(chinese( Mod((1/13 + O(5^n))^(1/3), 5^n), Mod((1/13 + O(2^n))^(1/3), 2^n)))), n)} \\ Following Andrew Howroyd's code for A319740.
Formula
a(n) = 9 - A306555(n) for n >= 2.
Comments