%I #14 Apr 04 2020 21:24:49
%S 1,1,1,1,1,1,1,1,4,1,1,4,1,1,4,1,1,4,1,1,4,1,1,4,6,1,4,1,1,9,1,1,4,1,
%T 6,4,1,1,4,6,1,4,1,1,9,1,1,4,8,6,4,1,1,4,6,8,4,1,1,9,1,1,11,1,6,4,1,1,
%U 4,13,1,4,1,1,9,1,8,4,1,6,13,1,1,11,6,1,4,1
%N Sum of odd divisors of n <= sqrt(n).
%C a(n) = Sum{d : d = A182469(n,k), d <= A000196(n), k=1..A001227(n)}. - _Reinhard Zumkeller_, Apr 05 2015
%H Reinhard Zumkeller, <a href="/A069289/b069289.txt">Table of n, a(n) for n = 1..10000</a>
%F G.f.: Sum_{k>=1} (2*k - 1) * x^((2*k - 1)^2) / (1 - x^(2*k - 1)). - _Ilya Gutkovskiy_, Apr 04 2020
%t Table[Total[Select[Divisors[n],OddQ[#]&&#<=Sqrt[n]&]],{n,120}] (* _Harvey P. Dale_, Jul 16 2017 *)
%o (PARI) a(n) = my(ir = sqrtint(n)); sumdiv(n, d, (d % 2) * (d <= ir) * d); \\ _Michel Marcus_, Jan 14 2014
%o (Haskell)
%o a069289 n = sum $ takeWhile (<= a000196 n) $ a182469_row n
%o -- _Reinhard Zumkeller_, Apr 05 2015
%Y Cf. A000593, A000203, A069288.
%Y Cf. A000196, A182469, A001227.
%K nonn
%O 1,9
%A _Reinhard Zumkeller_, Mar 14 2002