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A069289 Sum of odd divisors of n <= sqrt(n). 11
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, 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, 4, 13, 1, 4, 1, 1, 9, 1, 8, 4, 1, 6, 13, 1, 1, 11, 6, 1, 4, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,9

COMMENTS

a(n) = Sum{d : d = A182469(n,k), d <= A000196(n), k=1..A001227(n)}. - Reinhard Zumkeller, Apr 05 2015

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

FORMULA

G.f.: Sum_{k>=1} (2*k - 1) * x^((2*k - 1)^2) / (1 - x^(2*k - 1)). - Ilya Gutkovskiy, Apr 04 2020

MATHEMATICA

Table[Total[Select[Divisors[n], OddQ[#]&&#<=Sqrt[n]&]], {n, 120}] (* Harvey P. Dale, Jul 16 2017 *)

PROG

(PARI) a(n) = my(ir = sqrtint(n)); sumdiv(n, d, (d % 2) * (d <= ir) * d); \\ Michel Marcus, Jan 14 2014

(Haskell)

a069289 n = sum $ takeWhile (<= a000196 n) $ a182469_row n

-- Reinhard Zumkeller, Apr 05 2015

CROSSREFS

Cf. A000593, A000203, A069288.

Cf. A000196, A182469, A001227.

Sequence in context: A316584 A146325 A333807 * A341309 A346778 A097322

Adjacent sequences:  A069286 A069287 A069288 * A069290 A069291 A069292

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Mar 14 2002

STATUS

approved

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Last modified November 28 04:13 EST 2021. Contains 349400 sequences. (Running on oeis4.)