OFFSET
1,1
COMMENTS
LINKS
Robert Israel, Table of n, a(n) for n = 1..750
EXAMPLE
a(3) = 323 is a term because 323 = 17*19 with 17+19 = 36 = 6^2 and 324 = 2^2*3^4 with 2*2 + 4*3 = 16 = 4^2.
MAPLE
A:= select(proc(n) local t; issqr(add(t[1]*t[2], t=ifactors(n)[2])) end proc, {$1..10^5}):
B:= A intersect map(`-`, A, 1):
sort(convert(B, list));
MATHEMATICA
Module[{nn=65000, sq}, sq=Table[If[IntegerQ[Sqrt[Total[Times@@@FactorInteger[n]]]], 1, 0], {n, nn}]; SequencePosition[sq, {1, 1}]][[;; , 1]] (* Harvey P. Dale, Apr 12 2024 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert Israel, Jan 01 2023
STATUS
approved