A185961 Let d_1=1 < d_2 < d_3 < ... be the divisors of n; sequence lists positive numbers n such that for some k, n = 2(d_1 + ... + d_k).

2, 6, 12, 28, 40, 48, 224, 234, 496, 960, 8128, 47616, 174592, 10371840, 15037440, 28090368, 33550336, 134209536, 207516672, 492101632, 1150402560, 8589869056, 59205411720, 137438691328

Offset: 1

Author

N. J. A. Sloane, Feb 07 2011

Keywords

• nonn
• more

References

• Arie Groeneveld, Posting to Sequence Fans Mailing List, Feb 06, 2011

Crossrefs

Supersequence of A000396.

Cf. A064510, A185584, A185960.

Programs

PARI

forstep(n=2, 33550336, 2, d=divisors(n); s=0; for(j=1, numdiv(n), s=s+2*d[j]; if(s>=n, if(s==n, print1(n ", ")); next(2)))) \\ Donovan Johnson, Jan 24 2014

Extensions

a(14)-a(22) from Donovan Johnson, Feb 10 2011

a(23)-a(24) from Donovan Johnson, Jan 24 2014