OFFSET
1,2
COMMENTS
Conjecture: sequence is infinite.
No more terms below 10^9. - Amiram Eldar, Dec 27 2018
MATHEMATICA
subtract = If[ #1 < #2, Throw[ #1], #1 - #2]&; f[n_] := Catch @ Fold[subtract, n, Divisors @ n]; a = False; Do[b = IntegerQ[ Sqrt[ f[ n]]]; If[{a, b} == {True, True}, Print[n - 1]]; a = b, {n, 10^7}] (* Robert G. Wilson v, Jul 21 2005 *)
PROG
(PARI) a109883(n) = {my(r = n); fordiv(n, d, if (r < d, return (r)); r -= d; ); 0; }
isok(n) = issquare(a109883(n)) && issquare(a109883(n+1)); \\ Michel Marcus, Dec 28 2018
CROSSREFS
KEYWORD
more,nonn
AUTHOR
Jason Earls, Jul 18 2005
EXTENSIONS
a(10) from Amiram Eldar, Dec 27 2018
STATUS
approved