A371950 Weird numbers (A006037) whose sum of aliquot divisors is also a weird number.

97930, 132230, 146930, 191030, 205730, 215530, 244930, 259630, 279230, 308630, 362530, 411530, 440930, 524230, 529130, 583030, 597730, 602630, 632030, 646730, 705530, 730030, 808430, 891730, 921130, 955430, 970130, 1014230, 1024030, 1028930, 1102430, 1215130, 1435630

Offset

1,1

Comments

Terms k of A006037 such that A001065(k) is also a term of A006037.

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Wikipedia, Weird number.

Example

97930 is a term because it is a weird number, and A001065(97930) = sigma(97930) - 97930 = 103670 is also a weird number.

Mathematica

With[{weirds = Import["https://oeis.org/a006037/b006037.txt", "Table"][[;; , 2]]}, Select[weirds, (s = DivisorSigma[1, #] - #) <= Last[weirds] && MemberQ[weirds, s] &]]

Crossrefs

Subsequence of A006037 and A125639.

Cf. A000203 (sigma), A001065, A371951, A371952.

Sequence in context: A237509 A109185 A253823 * A316488 A235196 A002273

Adjacent sequences: A371947 A371948 A371949 * A371951 A371952 A371953

Keyword

nonn

Author

Amiram Eldar, Apr 14 2024

Status

approved