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%I #8 Apr 09 2014 10:15:49
%S 1,1,2,4,8,13,20,29,40,52,66,82,100,120,141,164,189,216,245,276,309,
%T 343,379,417,457,499,543,589,637,687,738,791,846,903,962,1023,1086,
%U 1151,1218,1287,1358,1430,1504,1580,1658,1738,1820,1904,1990,2078,2168
%N a(1) = 1, a(m+1) = sum_{k=1 to m}[min(m, a(k))].
%C This sequence can also be defined as follows: a(n) is the unique sequence such that a(1) = a(2) = 1 and the second differences of a(n) are 2, except that the a(n)th second difference is 1 for all n. In other words, if b(n) = a(n+2) - 2a(n+1) + a(n) is the second-difference function for a(n), x(n) = 2 - b(n) is the characteristic function for a(n). - _Joel B. Lewis_, Mar 16 2007
%e a(6) = min(5,1) + min(5,1) + min(5,2) + min(5,4) + min(5,8) = 1 + 1 + 2 + 4 + 5 = 13.
%K easy,nonn
%O 1,3
%A _Leroy Quet_, Aug 04 2000
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