|
|
A134733
|
|
Concatenation of next n imperfect numbers.
|
|
1
|
|
|
1, 23, 457, 891011, 1213141516, 171819202122, 23242526272930, 3132333435363738, 394041424344454647, 48495051525354555657, 5859606162636465666768, 697071727374757677787980
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
LINKS
|
|
|
MATHEMATICA
|
Module[{nn=120, in, len}, in=Select[Range[nn], DivisorSigma[1, #]!=2#&]; len= Floor[x/.Last[Solve[(x(x+1))/2==Length[in]]]]; FromDigits[Flatten[ IntegerDigits/@ #]]&/@TakeList[in, Range[len]]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Mar 01 2020 *)
|
|
CROSSREFS
|
|
|
KEYWORD
|
base,easy,nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|