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%I #13 Mar 02 2023 16:53:23
%S 1,1,3,1,1,6,1,1,3,5,1,6,1,1,8,1,1,6,1,5,9,1,1,6,1,1,3,8,1,15,1,1,3,1,
%T 1,14,1,1,3,5,1,12,1,1,17,1,1,6,1,5,3,1,1,6,11,8,3,1,1,15,1,1,9,1,1,
%U 17,1,1,3,5,1,14,1,1,8,1,1,18,1,5,3,1,1,19,1,1,3,1,1,24,14,1,3,1,1,6,1,1
%N a(n) = Sum_{d|2*n,d+1|2*n} d.
%H Antti Karttunen, <a href="/A069972/b069972.txt">Table of n, a(n) for n = 1..20000</a>
%F G.f.: (conjectured) Sum_{n>=1} n*x^(n*(n+1)/2)/(1-x^(n*(n+1)/2)). - _Joerg Arndt_, Jan 30 2011
%o (PARI) A069972(n) = { n = 2*n; sumdiv(n,d,if(!(n%(1+d)), d, 0)); }; \\ _Antti Karttunen_, Mar 02 2023
%Y Cf. A007862.
%K easy,nonn
%O 1,3
%A _Vladeta Jovovic_, Apr 29 2002
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