A070311 Numbers n such that sopfr(n) and d(n) are both perfect numbers.

338, 2496, 3520, 153280, 508096, 678592, 1162432, 1461952, 2130112, 2475712, 2595520, 2959552, 3042496, 3388096, 3443392, 3581632, 3733696, 3742912, 3744873, 5713173, 9492309, 11912896, 14767353, 15009472, 18021609, 21703125

Offset

1,1

Links

Donovan Johnson, Table of n, a(n) for n = 1..300

Prog

(PARI) {for(n=1, 22000000, d=numdiv(n); if(d==sigma(d)-d, s=0; F=factor(n); for(i=1, matsize(F)[1], s=s+F[i, 1]*F[i, 2]); if(s==sigma(s)-s, print1(n, ", "))))}

Crossrefs

Cf. A000396, A000005, A001414.

Sequence in context: A250802 A186052 A186044 * A205648 A221799 A059976

Adjacent sequences: A070308 A070309 A070310 * A070312 A070313 A070314

Keyword

nonn

Author

Jason Earls, May 10 2002

Extensions

More terms from Klaus Brockhaus, May 15 2002

Status

approved