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A193337 Sum of odd divisors of sigma(n). 2
1, 4, 1, 8, 4, 4, 1, 24, 14, 13, 4, 8, 8, 4, 4, 32, 13, 56, 6, 32, 1, 13, 4, 24, 32, 32, 6, 8, 24, 13, 1, 104, 4, 40, 4, 112, 20, 24, 8, 78, 32, 4, 12, 32, 56, 13, 4, 32, 80, 128, 13, 57, 40, 24, 13, 24, 6, 78, 24, 32, 32, 4, 14, 128, 32, 13, 18, 104, 4, 13, 13, 336, 38, 80, 32, 48, 4, 32, 6, 128, 133 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

sigma(n) = sum of divisors of n: A000203 (also called sigma_1(n)).

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..16384

Index entries for sequences related to sigma(n)

Index entries for sequences related to sums of divisors

FORMULA

a(n) = A000593(A000203(n)). - Michel Marcus, Jan 14 2014

a(n) + A193336(n) = A051027(n). - Antti Karttunen, Nov 18 2017

EXAMPLE

a(8) = 24 because sigma(8) = 15 and the sum of the 4 odd divisors  { 1, 3, 5, 15} is 24.

MATHEMATICA

Table[Total[Select[Divisors[DivisorSigma[1, n]], OddQ[ # ]&]], {n, 60}]

PROG

(PARI) a(n) = sumdiv(sigma(n), d, (d%2)*d); \\ Michel Marcus, Jan 14 2014

CROSSREFS

Cf. A000203, A051027, A193335, A193336.

Sequence in context: A096051 A060440 A021709 * A141567 A254707 A134417

Adjacent sequences:  A193334 A193335 A193336 * A193338 A193339 A193340

KEYWORD

nonn

AUTHOR

Michel Lagneau, Jul 23 2011

EXTENSIONS

More terms from Antti Karttunen, Nov 18 2017

STATUS

approved

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Last modified March 22 17:25 EDT 2019. Contains 321422 sequences. (Running on oeis4.)