A237286 Numbers m such that sigma(m) - m is a perfect number (A000396).

6, 25, 28, 496, 652, 8128, 10682, 10828, 33550336, 44655764, 8589869056, 8623554304, 137438691328, 1818115423731250112, 2305843008139952128, 2342443690808840128

Offset

1,1

Comments

Also numbers m such that A001065(m) is in A000396.

Up to a(13), note that the terms that are not perfect are deficient. - Michel Marcus, Mar 12 2014

a(14) is abundant. - Max Alekseyev, Jul 08 2026

Links

Table of n, a(n) for n=1..16.

Example

Number 25 is a term because sigma(25) - 25 = 31 - 25 = 6 (perfect number).

Prog

(PARI) isok(n) = sigma(smn=sigma(n) - n) == 2*smn; \\ Michel Marcus, Mar 01 2014

Crossrefs

Supersequence of A000396.

Cf. A000203, A235710, A279359, A291373, A378099.

Sequence in context: A136606 A074096 A126016 * A046416 A042879 A042495

Adjacent sequences: A237283 A237284 A237285 * A237287 A237288 A237289

Keyword

nonn,more,changed

Author

Jaroslav Krizek, Feb 28 2014

Extensions

a(10) from Michel Marcus, Mar 01 2014

a(11)-a(13) from Giovanni Resta, Mar 01 2014

a(14)-a(16) from Max Alekseyev, Jul 09 2026

Status

approved