A294927 - OEIS

%I #11 Mar 14 2024 03:47:22

%S 0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,2,0,0,0,0,0,1,0,0,0,0,

%T 0,3,0,0,0,1,0,1,0,0,0,0,0,3,0,0,0,0,0,2,0,1,0,0,0,4,0,0,0,0,0,1,0,0,

%U 0,0,0,5,0,0,0,0,0,1,0,2,0,0,0,4,0,0,0,0,0,3,0,0,0,0,0,4,0,0,0,1,0,1,0,0,0

%N Number of proper divisors of n that are nondeficient (A023196).

%H Antti Karttunen, <a href="/A294927/b294927.txt">Table of n, a(n) for n = 1..20000</a>

%F a(n) = Sum_{d|n, d<n} A294936(d).

%F a(n) + A294926(n) = A032741(n).

%t a[n_] := DivisorSum[n, 1 &, # < n && DivisorSigma[1, #] >= 2*# &]; Array[a, 100] (* _Amiram Eldar_, Mar 14 2024 *)

%o (PARI) A294927(n) = sumdiv(n, d, (d<n)*(sigma(d)>=(2*d)));

%Y Cf. A023196, A032741, A071395, A294887, A294926, A294928, A294929, A294936.

%K nonn

%O 1,24

%A _Antti Karttunen_, Nov 14 2017