A294927 Number of proper divisors of n that are nondeficient (A023196).

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, 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, 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

Offset

1,24

Links

Antti Karttunen, Table of n, a(n) for n = 1..20000

Formula

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

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

Mathematica

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

Prog

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

Crossrefs

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

Sequence in context: A325801 A325194 A066087 * A080224 A341508 A261488

Adjacent sequences: A294924 A294925 A294926 * A294928 A294929 A294930

Keyword

nonn

Author

Antti Karttunen, Nov 14 2017

Status

approved