OFFSET
1,1
LINKS
Paolo Xausa, Table of n, a(n) for n = 1..14
FORMULA
a(n) = A139228(n)/2.
MATHEMATICA
Differences[Select[Range[10000], DivisorSigma[1, #] == 2# &]]/2 (* Alonso del Arte, Mar 05 2020 *)
Differences[PerfectNumber[Range[12]]]/2 (* Paolo Xausa, Oct 20 2023 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Omar E. Pol, Apr 19 2008
EXTENSIONS
a(6)-a(9) from A139228(n)/2 by Jinyuan Wang, Mar 04 2020
STATUS
approved