A182227 Sum of divisors of the abundant number m = A005101(n) which are smaller than its abundance A033880(m).

6, 3, 1, 24, 27, 55, 20, 19, 76, 21, 14, 108, 23, 3, 123, 12, 66, 140, 3, 144, 156, 22, 12, 1, 172, 52, 12, 240, 123, 204, 12, 126, 259, 147, 236, 138, 66, 312, 12, 42, 546, 12, 316, 7, 171, 165, 198, 44, 366, 384, 174, 12, 112, 218, 117, 744, 12, 476, 12, 198

Offset

1,1

Comments

Motivated by A100696. See also A182225 and A182226.

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..1000 from M. F. Hasler)

Mathematica

f[n_] := If[(ab = DivisorSigma[1, n] - 2*n) > 0 , DivisorSum[n, # &, # < ab &], Nothing]; Array[f, 300] (* Amiram Eldar, Apr 06 2024 *)

Prog

(PARI) f(n)=my(A=sigma(n)-2*n, s); fordiv(n, d, (d<A && s+=d) || break); s
for(n=1, 500, sigma(n)>2*n & print1(f(n)", "))

Crossrefs

Cf. A005101, A033880, A100696, A182225, A182226.

Sequence in context: A119743 A272643 A243424 * A108451 A122178 A126445

Adjacent sequences: A182224 A182225 A182226 * A182228 A182229 A182230

Keyword

nonn

Author

M. F. Hasler, Apr 19 2012

Status

approved