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A195210 Sum of odd divisors of !n. 0

%I

%S 1,0,1,1,13,12,324,1352,18368,19152,1994322,8810748,193690826,

%T 829046868,34563283272,274895151856,14554448767872,8178592487376,

%U 2493850026398472,33842416675133248,1037660717168380800,6072370562498569056

%N Sum of odd divisors of !n.

%C !n is a subfactorial number (A000166).

%C Property of the sequence: for n> 4 the sum of odd divisors of !n seems even.

%e a(7) = 1352 because the divisors of !7 = 1854 are {1, 2, 3, 6, 9, 18, 103, 206, 309, 618, 927, 1854}, and the sum of the 6 odd divisors 1, 3, 9, 103, 309 and 927 is 1352.

%t Table[Total[Select[Divisors[Subfactorial[n]], OddQ[ # ]&]], {n, 0, 21}]

%Y Cf. A000166, A195208.

%K nonn

%O 0,5

%A _Michel Lagneau_, Sep 13 2011

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Last modified December 11 18:34 EST 2019. Contains 329925 sequences. (Running on oeis4.)