cp's OEIS Frontend

A348074 a(n) = A035327(n) if n is even, 3n + 1 if n is odd.

%I A348074 #46 Dec 21 2022 04:49:36
%S A348074 1,4,1,10,3,16,1,22,7,28,5,34,3,40,1,46,15,52,13,58,11,64,9,70,7,76,5,
%T A348074 82,3,88,1,94,31,100,29,106,27,112,25,118,23,124,21,130,19,136,17,142,
%U A348074 15,148,13,154,11,160,9,166,7,172,5,178,3,184,1,190,63
%N A348074 a(n) = A035327(n) if n is even, 3n + 1 if n is odd.
%e A348074 n    parity   function       a(n)
%e A348074 =    =====    =========     ======
%e A348074 0     even    A035327(0)      1
%e A348074 1     odd      3*1 + 1        4
%e A348074 2     even    A035327(2)      1
%e A348074 3     odd      3*3 + 1       10
%e A348074 4     even    A035327(4)      3
%e A348074 5     odd      3*5 + 1       16
%o A348074 (Python)
%o A348074 def A348074(n):
%o A348074     if n%2==0:
%o A348074         if n==0: return 1
%o A348074         else: return (1<<int.bit_length(n)) - n - 1 #A035327(n)
%o A348074     else: return 3*n+1
%o A348074 (Python)
%o A348074 def A348074(n): return 3*n+1 if n&1 or n==0 else (~n)^(-1<<n.bit_length()) # _Chai Wah Wu_, Dec 20 2022
%Y A348074 Cf. A006370, A035327.
%K A348074 nonn
%O A348074 0,2
%A A348074 _Alexander Van Plantinga_, Sep 27 2021