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Positions where A109890(n) = Sum_{i = 1..n-1} A109890(i).
4

%I #8 Mar 04 2018 03:15:03

%S 3,4,222,232,279,568,634,844,1307,1704,2016,2050,2164,2325,2701,3130,

%T 3225,3322,3524,4673,6007,6692,7141,7221,7954,8689,11051,11898,13959,

%U 14166,16192,17078,17220,17521,18071,22324,22414,24757,28290,28979

%N Positions where A109890(n) = Sum_{i = 1..n-1} A109890(i).

%C These are the positions where A109735(n) = 2*A109735(n-1), or equally, where A111241(n) = 1.

%o (PARI) s = 3; S = Set([1, 2]); i = 3; while (1, d = divisors(s); j = 1; while (setsearch(S, d[j]), j++); n = d[j]; if (n == s, print(i)); s += n; S = setunion(S, Set(n)); i++); \\ _David Wasserman_, Jan 09 2009

%Y Cf. A109890, A109735, A111316, A111241.

%K nonn

%O 1,1

%A _N. J. A. Sloane_, Nov 04 2005

%E More terms from _David Wasserman_, Jan 09 2009