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A186644 The sum of the oex divisors of n. 2
1, 3, 4, 5, 6, 12, 8, 15, 10, 18, 12, 26, 14, 24, 24, 25, 18, 36, 20, 40, 32, 36, 24, 60, 26, 42, 40, 54, 30, 72, 32, 59, 48, 54, 48, 80, 38, 60, 56, 90, 42, 96, 44, 82, 75, 72, 48, 118, 50, 88, 72, 96, 54, 120, 72, 120, 80, 90, 60, 166, 62, 96, 101, 117, 84, 144, 68, 124, 96, 144, 72, 186, 74, 114, 119, 138, 96 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

See A186643 for a definition of which divisors of n are classified as oex divisors.

LINKS

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

FORMULA

a(n) >= A049417(n).

MAPLE

maxval := proc(n, d) local nshf, a ; if n mod d <> 0 then 0; else nshf := n ; a := 0 ; while nshf mod d = 0 do nshf := nshf /d ; a := a+1 ; end do: a; end if; end proc:

A186644 := proc(n) a := 1 ; for d in numtheory[divisors](n) minus {1} do if type(maxval(n, d), 'odd') then a := a+d ; end if; end do: a ; end proc: # R. J. Mathar, Mar 04 2011

MATHEMATICA

Table[DivisorSum[n, # &, Or[# == 1, OddQ@ IntegerExponent[n, #]] &], {n, 77}] (* Michael De Vlieger, Nov 23 2017 *)

PROG

(PARI) a(n) = sumdiv(n, d, d*((d==1) || (valuation(n, d) % 2))); \\ Michel Marcus, Feb 06 2016

CROSSREFS

Cf. A186643, A000203, A049417, A050376.

Sequence in context: A324706 A049417 A188999 * A125139 A107224 A026493

Adjacent sequences:  A186641 A186642 A186643 * A186645 A186646 A186647

KEYWORD

nonn

AUTHOR

Vladimir Shevelev, Feb 25 2011

EXTENSIONS

More terms from Antti Karttunen, Nov 23 2017

STATUS

approved

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Last modified October 21 22:47 EDT 2019. Contains 328315 sequences. (Running on oeis4.)