A085062 - OEIS

%I #22 Aug 31 2024 08:30:36

%S 0,1,1,4,2,4,3,13,4,7,5,13,6,10,7,40,8,13,9,22,10,16,11,40,12,19,13,

%T 31,14,22,15,121,16,25,17,40,18,28,19,67,20,31,21,49,22,34,23,121,24,

%U 37,25,58,26,40,27,94,28,43,29,67,30,46,31,364,32,49,33,76,34,52,35,121,36,55

%N a(n) = A085060(n)/9 - 1/3.

%C Interlacing of A001477 and A085060 / 3. - _Ruud H.G. van Tol_, Aug 30 2024

%H Alois P. Heinz, <a href="/A085062/b085062.txt">Table of n, a(n) for n = 0..10000</a>

%H J. C. Lagarias and N. J. A. Sloane, Approximate squaring (<a href="http://neilsloane.com/doc/apsq.pdf">pdf</a>, <a href="http://neilsloane.com/doc/apsq.ps">ps</a>), Experimental Math., 13 (2004), 113-128.

%F a(n) mod 2 = A292077(n+1). - _Alois P. Heinz_, Jul 01 2023

%F a(2*n) = n; a(2*n+1) = 3 * a(n) + 1. - _Ruud H.G. van Tol_, Aug 31 2024

%p a:= n-> `if`(n::odd, a((3*n+1)/2), n/2):

%p seq(a(n), n=0..100);  # _Alois P. Heinz_, Jul 01 2023

%o (PARI) a(n) = ((3/2)^valuation(n++, 2)*n-1)/2; \\ _Ruud H.G. van Tol_, Aug 30 2024

%Y Cf. A085060, A292077.

%Y Bisection gives: A001477 (even part).

%K nonn

%O 0,4

%A _N. J. A. Sloane_, Aug 11 2003