cp's OEIS Frontend

A167209 a(0) = 0; for n>=0, a(n+1) = a(n) + x where x is the smallest nonnegative number which is not equal to a(i) +/- a(k) or a(i)/2 for any 0<=i<=n, 0<=k<=n.

%I A167209 #34 Feb 18 2019 13:58:14
%S A167209 0,1,4,10,17,29,44,67,91,117,148,180,215,251,288,329,371,420,471,523,
%T A167209 576,631,687,746,806,870,935,1004,1074,1146,1221,1297,1376,1456,1538,
%U A167209 1623,1709,1802,1896,1993,2092,2194,2300,2409,2519,2631,2753,2876,3001,3127,3255,3385,3518,3655,3796,3939
%N A167209 a(0) = 0; for n>=0, a(n+1) = a(n) + x where x is the smallest nonnegative number which is not equal to a(i) +/- a(k) or a(i)/2 for any 0<=i<=n, 0<=k<=n.
%C A167209 A maximal expulsion set of natural numbers.
%C A167209 Note that this definition is different from that of A047699.
%H A167209 Rémy Sigrist, <a href="/A167209/b167209.txt">Table of n, a(n) for n = 0..10000</a>
%H A167209 K. S. Brown, <a href="http://www.mathpages.com/home/kmath509/kmath509.htm">Expulsion Sets</a>
%H A167209 Rémy Sigrist, <a href="/A167209/a167209.txt">C program for A167209</a>
%o A167209 (C) See Links section.
%Y A167209 Cf. A169799, A169820, A047699.
%K A167209 nonn
%O A167209 0,3
%A A167209 _N. J. A. Sloane_, Sep 03 2014
%E A167209 Initial value changed to a(0)=0 by _N. J. A. Sloane_, Feb 18 2019 (otherwise the definition did not match the terms).