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Number of digits of n plus number of digits of n equal to 1, 2, 4, or 8.
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%I #22 Aug 03 2021 20:23:28

%S 2,2,1,2,1,1,1,2,1,3,4,4,3,4,3,3,3,4,3,3,4,4,3,4,3,3,3,4,3,2,3,3,2,3,

%T 2,2,2,3,2,3,4,4,3,4,3,3,3,4,3,2,3,3,2,3,2,2,2,3,2,2,3,3,2,3,2,2,2,3,

%U 2,2,3,3,2,3,2,2,2,3,2,3,4,4,3,4,3,3,3

%N Number of digits of n plus number of digits of n equal to 1, 2, 4, or 8.

%H Robert Israel, <a href="/A218450/b218450.txt">Table of n, a(n) for n = 1..10000</a>

%F lim inf a(n)/log_10 n = 1; lim sup a(n)/log_10 n = 2.

%p f:= proc(n) local L;

%p L:= convert(n,base,10);

%p nops(L) + numboccur(L,{1,2,4,8})

%p end proc:

%p map(f, [$1..100]); # _Robert Israel_, Apr 29 2021

%t Table[d = IntegerDigits[n]; Length[d] + Count[d, 1] + Count[d, 2] + Count[d, 4] + Count[d, 8], {n, 100}] (* _T. D. Noe_, Nov 16 2012 *)

%t Table[IntegerLength[n]+Total[DigitCount[n,10,{1,2,4,8}]],{n,100}] (* _Harvey P. Dale_, Aug 03 2021 *)

%o (PARI) a(n) = my(d = digits(n)); #d + #select(x->((x==1) || (x==2) || (x==4) || (x==8)), d); \\ _Michel Marcus_, Jan 31 2016

%K nonn,easy,base

%O 1,1

%A _David Williams_, Oct 28 2012