A309476 One of the two successive approximations up to 3^n for the 3-adic integer sqrt(-1/2).

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

Offset: 0

Author

Seiichi Manyama, Aug 04 2019

Keywords

• nonn

Examples

			a(1) = (   1)_3 = 1,
a(2) = (  21)_3 = 7,
a(3) = ( 121)_3 = 16,
a(4) = (2121)_3 = 70.
		

Links

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

Crossrefs

Cf. A268924, A309474, A309477.

Programs

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

PARI

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