Search: id:A030057
Results 1-1 of 1 results found.

%I A030057
%S A030057 2,4,2,8,2,13,2,16,2,4,2,29,2,4,2,32,2,40,2,43,2,4,2,61,2,4,2,57,2,73,
               2,
%T A030057 64,2,4,2,92,2,4,2,91,2,97,2,8,2,4,2,125,2,4,2,8,2,121,2,121,2,4,2,169,
%U A030057 2,4,2,128,2,145,2,8,2,4,2,196,2,4,2,8,2,169,2,187,2,4,2,225,2,4,2,181
%N A030057 Least number which is not a sum of distinct divisors of n.
%C A030057 a(n)=2 if and only if n is odd. a(2^n)=2^(n+1). - Emeric Deutsch (deutsch(AT)duke.poly.edu), 
               Aug 07 2005
%H A030057 David Wasserman (dwasserm(AT)earthlink.net), Apr 24 2007, <a href="b030057.txt">
               Table of n, a(n) for n = 1..1000</a>
%e A030057 a(10)=4 because 4 is the least positive integer that is not a sum of 
               distinct divisors (namely 1,2,5 and 10) of 10.
%p A030057 with(combinat): with(numtheory): for n from 1 to 100 do div:=powerset(divisors(n)): 
               b[n]:=sort({seq(sum(div[i][j],j=1..nops(div[i])),i=1..nops(div))}) 
               od: for n from 1 to 100 do B[n]:={seq(k,k=0..1+sigma(n))} minus b[n] 
               od: seq(B[n][1],n=1..100); (Deutsch)
%Y A030057 Cf. A005153, A093896.
%Y A030057 Sequence in context: A073017 A059866 A093895 this_sequence A134066 A090988 
               A095728
%Y A030057 Adjacent sequences: A030054 A030055 A030056 this_sequence A030058 A030059 
               A030060
%K A030057 nonn,nice
%O A030057 1,1
%A A030057 David W. Wilson (davidwwilson(AT)comcast.net)
%E A030057 Edited by N. J. A. Sloane (njas(AT)research.att.com), May 05 2007

Search completed in 0.001 seconds