A241989 - OEIS

%I #28 Jun 12 2017 10:19:23

%S 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,18,20,30,32,33,35,36,40,45,48,

%T 50,54,60,64,65,66,70,72,75,80,90,96,99,100,105,108,112,120,126,128,

%U 130,132,135,140,144,150,160,165,175,176,180,192,195,198,200

%N Positive numbers n that are divisible by the sum of the digits of n in base 16.

%C A base 16 version of Harshad (or Niven) numbers (A005349).

%C Numbers n such that n = 0 modulo A053836(n). - _Antti Karttunen_, Aug 22 2014

%H Chai Wah Wu, <a href="/A241989/b241989.txt">Table of n, a(n) for n = 1..10000</a>

%e 82478 is in the sequence as it is 1422E in hexadecimal and 1+4+2+2+14 = 23 which divides 82478.

%t Select[Range[200], Divisible[#, Total@ IntegerDigits[#, 16]] &] (* _Indranil Ghosh_, Jun 12 2017 *)

%o (Python)

%o from gmpy2 import digits

%o A241989 = [n for n in range(1,10**3) if not n % sum([int(d,16) for d in digits(n,16)])]

%o (MIT/GNU Scheme, with _Antti Karttunen_'s IntSeq-library)

%o (define A241989 (MATCHING-POS 1 1 (lambda (n) (zero? (modulo n (A053836 n))))))

%o (define (A053836 n) (let loop ((n n) (i 0)) (if (zero? n) i (loop (floor->exact (/ n 16)) (+ i (modulo n 16))))))

%Y Cf. A005349, A053836, A245802.

%K nonn,base

%O 1,2

%A _Chai Wah Wu_, Aug 22 2014