|
Search: id:A070310
|
|
|
| A070310 |
|
Numbers n such that the sum of its aliquot parts and the number of its divisors are both perfect numbers. |
|
+0
1
|
| |
|
|
OFFSET
|
1,1
|
|
|
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}]
|
|
PROGRAM
|
(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: A004371 A089908 A038121 this_sequence A160141 A004293 A012808
Adjacent sequences: A070307 A070308 A070309 this_sequence A070311 A070312 A070313
|
|
KEYWORD
|
more,nonn,bref
|
|
AUTHOR
|
Jason Earls (zevi_35711(AT)yahoo.com), May 10 2002
|
|
EXTENSIONS
|
Edited by Robert G. Wilson v (rgwv(AT)rgwv.com), May 14 2002
No further terms below 10^8. Is the sequence complete? - Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), May 17 2002
|
|
|
Search completed in 0.002 seconds
|
