A107130 - OEIS

%I #15 Apr 07 2022 23:44:29

%S 0,0,2,1,4,2,6,3,8,4,0,0,2,1,4,2,6,3,8,4,20,20,22,21,24,22,26,23,28,

%T 24,10,10,12,11,14,12,16,13,18,14,40,40,42,41,44,42,46,43,48,44,20,20,

%U 22,21,24,22,26,23,28,24,60,60,62,61,64,62,66,63,68,64,30,30,32,31,34,32

%N Replace each odd digit d of n with (d-1)/2.

%C Differs from A065423 starting with a(10) = 0, A065423(10) = 10.

%H Vincenzo Librandi, <a href="/A107130/b107130.txt">Table of n, a(n) for n = 0..5000</a>

%t a[n_]:=FromDigits[Map[If[Mod[ #, 2]==1, (#-1)/2, # ]&, IntegerDigits[n]]];Table[a[n], {n, 0, 100}]

%o (Python)

%o def A107130(n): return int(str(n).translate({49:48,51:49,53:50,55:51,57:52})) # _Chai Wah Wu_, Apr 07 2022

%o (PARI) a(n)=fromdigits(apply(d->if(d%2,d\2,d),digits(n))) \\ _Charles R Greathouse IV_, Apr 07 2022

%Y Cf. A065423.

%K nonn,base,easy

%O 0,3

%A _Zak Seidov_, May 12 2005

%E Edited by _Charles R Greathouse IV_, Aug 03 2010