Search: id:A144261
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%I A144261
%S A144261 1,1,1,1,1,1,1,1,1,1,10,1,9,3,2,3,6,1,6,1,1,5,9,1,2,6,1,3,9,1,12,6,4,3,
%T A144261 2,1,3,3,3,1,10,1,12,3,1,5,9,1,8,1,2,3,18,1,2,2,2,9,9,1,12,6,1,3,3,2,3,
%U A144261 3,3,1,18,1,7,3,2,2,4,2,9,1,1,5,18,1,6,6,3,3,9,1,4,5,4,9,2,2,12,4,2,1
%N A144261 a(n) = smallest k such that k*n is a Niven (or Harshad) number.
%C A144261 Niven (or Harshad) numbers are numbers that are divisible by the sum 
               of their digits.
%C A144261 Does a(n) exist for all n? - Klaus Brockhaus, Sep 19 2008
%H A144261 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               HarshadNumber.html">Harshad Number</a>
%e A144261 a(14) = 3 since neither 1*14 or 2*14 are Niven numbers, but 3*14 = 42 
               is a Niven number: 42 = 7*(4+2).
%o A144261 (PARI) digitsum(n) = {local(s=0); while(n, s+=n%10; n\=10); s} {for(n=1, 
               100, k=1; while((p=k*n)%digitsum(p)>0, k++); print1(k, ","))} /* 
               Klaus Brockhaus, Sep 19 2008 */
%Y A144261 Cf. A005349 (Niven numbers), A144262 (smallest k such that k*n is not 
               a Niven number), A144363 (records in A144261), A144364 (where records 
               occur in A144261).
%Y A144261 Sequence in context: A105162 A010184 A107830 this_sequence A046148 A164915 
               A010691
%Y A144261 Adjacent sequences: A144258 A144259 A144260 this_sequence A144262 A144263 
               A144264
%K A144261 base,nonn
%O A144261 1,11
%A A144261 Sergio Pimentel (ferdiego(AT)suddenlink.net), Sep 16 2008
%E A144261 Edited and extended by Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), 
               Sep 19 2008

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