A116974 Numbers n for which the sum of the proper divisors equals the product of the proper divisors.

2, 3, 5, 6, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277

Offset: 1

Author

Luc Stevens (lms022(AT)yahoo.com), Apr 01 2006

Keywords

• nonn
• easy

Programs

Mathematica

fQ[n_] := Block[{id = Most@Divisors@n}, Plus @@ id == Times @@ id]; Select[Range@300, fQ@# &] (* Robert G. Wilson v, Apr 03 2006 *)

PARI

a(n)=if(n<5,[2,3,5,6][n],prime(n+1)) \\ Charles R Greathouse IV, Aug 26 2011

Formula

Union of 6 and A000040: the prime numbers.