OFFSET
1,1
LINKS
Jan Munch Pedersen, Known Perfect Numbers [Steven Bi (chenhsi(AT)stanford.edu), Jan 18 2009]
Omar E. Pol, Los numeros perfectos
MATHEMATICA
Join[{6}, FromDigits[Take[IntegerDigits[#], 2]]&/@PerfectNumber[Range[2, 50]]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Sep 26 2020 *)
CROSSREFS
KEYWORD
base,more,nonn
AUTHOR
Omar E. Pol, Apr 02 2008
EXTENSIONS
a(15)-a(31) added by Steven Bi (chenhsi(AT)stanford.edu), Jan 18 2009
Definition changed (inserting the word "even") and a(37)-a(47) added by Ivan Panchenko, Aug 04 2018
STATUS
approved