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%I #17 Feb 03 2022 08:53:19
%S 1,2,3,4,5,7,8,9,10,11,13,14,15,16,17,19,20,21,22,23,25,26,27,29,31,
%T 32,33,35,37,38,39,41,43,44,45,47,49,50,51,53,55,57,59,61,63,65,67,69,
%U 71,73,75,77,79,81,83,85,87,89,91,93,95,97,99,101,103,105
%N Numbers that cannot be written as sum of perfect numbers.
%C Complement of A204879; A097796(a(n)) = 0.
%H Reinhard Zumkeller, <a href="/A204878/b204878.txt">Table of n, a(n) for n = 1..1000</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/PerfectNumber.html">Perfect Number</a>
%H Wikipedia, <a href="http://www.wikipedia.org/wiki/Perfect_number">Perfect number</a>
%F a(38+k) = 49+2k for all k>0 (up to occurrence of an odd perfect number, known to be > 10^300, if it exists). - _M. F. Hasler_, Feb 09 2012
%o (Haskell)
%o import Data.List (elemIndices)
%o a204878 n = a204878_list !! (n-1)
%o a204878_list = map (+ 1) $ elemIndices 0 a097796_list
%Y Cf. A000396 (perfect numbers).
%K nonn
%O 1,2
%A _Reinhard Zumkeller_, Jan 20 2012
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