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A053836 Sum of digits of n written in base 16.

%I A053836 #34 Feb 16 2025 08:32:42
%S A053836 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,1,2,3,4,5,6,7,8,9,10,11,12,13,
%T A053836 14,15,16,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,3,4,5,6,7,8,9,10,11,
%U A053836 12,13,14,15,16,17,18,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,5,6,7
%N A053836 Sum of digits of n written in base 16.
%C A053836 a(n) = A138530(n,16) for n > 15. - _Reinhard Zumkeller_, Mar 26 2008
%H A053836 Reinhard Zumkeller, <a href="/A053836/b053836.txt">Table of n, a(n) for n = 0..10000</a>
%H A053836 Robert Walker, <a href="http://robertinventor.com/ftswiki/Self_Similar_Sloth_Canon_Number_Sequences">Self Similar Sloth Canon Number Sequences</a>
%H A053836 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Hexadecimal.html">Hexadecimal</a>
%H A053836 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/DigitSum.html">Digit Sum</a>
%F A053836 a(0)=0, a(16*n+i)=a(n)+i 0<=i<=15; a(n)=n-15*Sum_{k>0} floor(n/16^k). - _Benoit Cloitre_, Dec 19 2002
%e A053836 a(20) = 1 + 4 = 5 because 20 is written as "14" in base 16.
%t A053836 Table[Plus @@ IntegerDigits[n, 16], {n, 0, 150}] (* _Vladimir Joseph Stephan Orlovsky_, Jul 19 2011 *)
%o A053836 (PARI) a(n)=if(n<1,0,if(n%16,a(n-1)+1,a(n/16)))
%o A053836 (PARI) a(n) = sumdigits(n, 16); \\ _Michel Marcus_, Jan 19 2023
%o A053836 (Haskell)
%o A053836 a053836 n = q 0 $ divMod n 16 where
%o A053836    q r (0, d) = r + d
%o A053836    q r (m, d) = q (r + d) $ divMod m 16
%o A053836 -- _Reinhard Zumkeller_, May 15 2011
%o A053836 (Python)
%o A053836 def A053836(n): return sum(int(d,16) for d in hex(n)[2:]) # _Chai Wah Wu_, Jan 19 2023
%Y A053836 Cf. A000120, A007953.
%K A053836 base,nonn,easy
%O A053836 0,3
%A A053836 _Henry Bottomley_, Mar 28 2000