OFFSET
0,3
COMMENTS
a(n) = A138530(n,16) for n > 15. - Reinhard Zumkeller, Mar 26 2008
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 0..10000
Robert Walker, Self Similar Sloth Canon Number Sequences
Eric Weisstein's World of Mathematics, Hexadecimal
Eric Weisstein's World of Mathematics, Digit Sum
FORMULA
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
EXAMPLE
a(20) = 1 + 4 = 5 because 20 is written as "14" in base 16.
MATHEMATICA
Table[Plus @@ IntegerDigits[n, 16], {n, 0, 150}] (* Vladimir Joseph Stephan Orlovsky, Jul 19 2011 *)
PROG
(PARI) a(n)=if(n<1, 0, if(n%16, a(n-1)+1, a(n/16)))
(PARI) a(n) = sumdigits(n, 16); \\ Michel Marcus, Jan 19 2023
(Haskell)
a053836 n = q 0 $ divMod n 16 where
q r (0, d) = r + d
q r (m, d) = q (r + d) $ divMod m 16
-- Reinhard Zumkeller, May 15 2011
(Python)
def A053836(n): return sum(int(d, 16) for d in hex(n)[2:]) # Chai Wah Wu, Jan 19 2023
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Henry Bottomley, Mar 28 2000
STATUS
approved