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A309476 One of the two successive approximations up to 3^n for the 3-adic integer sqrt(-1/2). 3
0, 1, 7, 16, 70, 232, 475, 1933, 1933, 8494, 28177, 87226, 87226, 1150108, 2744431, 12310369, 12310369, 55357090, 313637416, 313637416, 1475898883, 1475898883, 1475898883, 32856958492, 221143316146, 221143316146, 1915720535032, 4457586363361, 12083183848348, 34959976303309 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Robert Israel, Table of n, a(n) for n = 0..2093

EXAMPLE

a(1) = (   1)_3 = 1,

a(2) = (  21)_3 = 7,

a(3) = ( 121)_3 = 16,

a(4) = (2121)_3 = 70.

MAPLE

N:= 30: # for a(0) to a(N)

with(padic):

A:= rootp(x^2+1/2, 3, N):

if ratvaluep(A[1], 1) = 1 then A:= A[1] else A:= A[2] fi:

seq(ratvaluep(A, i), i=0..N); # Robert Israel, May 11 2020

PROG

(PARI) {a(n) = truncate(sqrt(-1/2+O(3^n)))}

CROSSREFS

Cf. A268924, A309474, A309477.

Sequence in context: A183343 A318481 A215180 * A192376 A214904 A029498

Adjacent sequences:  A309473 A309474 A309475 * A309477 A309478 A309479

KEYWORD

nonn

AUTHOR

Seiichi Manyama, Aug 04 2019

STATUS

approved

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Last modified September 23 18:51 EDT 2020. Contains 337315 sequences. (Running on oeis4.)