A070310 Numbers n such that the sum of its aliquot parts and the number of its divisors are both perfect numbers.

28, 652, 10828

Offset

1,1

Comments

Subsequence of A237286. - Roderick MacPhee, Jan 19 2017

Links

Table of n, a(n) for n=1..3.

Mathematica

p = {6, 28, 496, 8128, 33550336}; Do[a = Divisors[n]; If[ Position[p, Plus @@ Drop[a, -1]] != {} && Position[p, Length[a]] != {}, Print[n]], {n, 1, 10^7}]

Prog

(PARI) {for(n=1, 10^8, d=numdiv(n); if(d==sigma(d)-d, s=sigma(n)-n; if(s==sigma(s)-s, print1(n, ", "))))}

Crossrefs

Cf. A000396, A001065, A000005.

Sequence in context: A038121 A240684 A184329 * A309804 A236753 A269473

Adjacent sequences: A070307 A070308 A070309 * A070311 A070312 A070313

Keyword

more,nonn,bref

Author

Jason Earls, May 10 2002

Extensions

Edited by Robert G. Wilson v, May 14 2002

No further terms below 10^8. Is the sequence complete? - Klaus Brockhaus, May 17 2002

Status

approved