A186644 The sum of the oex divisors of n.

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

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: A049417 A331110 A188999 * A337177 A125139 A369762

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