A101814 - OEIS

%I #15 Jan 19 2021 04:01:50

%S 2,4,6,8,10,12,18,20,24,30,36,40,42,48,50,54,60,70,72,80,84,90,100,

%T 102,108,110,112,114,120,126,132,140,144,150,152,156,162,180,190,192,

%U 198,200,204,210,216,220,222,224,228,230,234,240,252,264,266,270,280,288

%N Even Niven (or Harshad) numbers: even numbers that are divisible by the sum of their digits.

%D David Wells, The Penguin Dictionary of Curious and Interesting Numbers. Penguin Books, NY, 1986, p. 171.

%H Amiram Eldar, <a href="/A101814/b101814.txt">Table of n, a(n) for n = 1..10000</a>

%H Richard K. Guy, <a href="http://www.jstor.org/stable/2691503">The Second Strong Law of Small Numbers</a>, Math. Mag, Vol. 63, No. 1 (1990), pp. 3-20.

%e 216 is a term of the sequence because it is even and divisible by 9 (= 2+1+6).

%p s:=proc(n) local N:N:=convert(n,base,10):sum(N[j],j=1..nops(N)) end:p:=proc(n) if floor(n/s(n))=n/s(n) then n else fi end: seq(p(2*n),n=1..161);

%t Select[2*Range[200],Divisible[#,Total[IntegerDigits[#]]]&] (* _Harvey P. Dale_, May 08 2015 *)

%o (PARI) isok(n) = !(n%2) && !(n % sumdigits(n)); \\ _Michel Marcus_, Sep 19 2017

%Y Cf. A005349, A101813.

%K nonn,base

%O 1,1

%A _Emeric Deutsch_, Dec 16 2004

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