OFFSET
0,3
COMMENTS
Starting offset is zero, because a(0)=0 is a special case in this sequence.
LINKS
Antti Karttunen, Table of n, a(n) for n = 0..20763
MATHEMATICA
Take[Select[Sort@ DeleteDuplicates@ Table[n - DivisorSigma[0, n], {n, 20000}], IntegerQ@ Sqrt@ # &], 68] (* Michael De Vlieger, Oct 13 2015 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Oct 11 2015
STATUS
approved