A050710 Smallest composite that when added to sum of prime factors reaches a prime after n iterations.

6, 8, 4, 32, 49, 45, 60, 125, 82, 66, 150, 129, 559, 417, 358, 378, 314, 279, 247, 183, 1152, 1102, 2265, 1929, 1658, 1524, 1414, 5708, 8047, 6033, 8430, 8020, 7852, 11805, 11715, 9388, 12622, 13471, 13146, 12562, 12512, 20830, 16869, 13492, 58832

Offset

1,1

Links

Donovan Johnson, Table of n, a(n) for n = 1..200

Example

n = 2 gives a(2) = 8 -> 8 = 2*2*2 so 8 + (2+2+2) = 14 and composite (iteration 1); 14 = 2*7 so 14 + (2+7) = 23 and already prime after the second iteration.

Mathematica

a[n_]:=Length[NestWhileList[#+Total[Times@@@FactorInteger[#]]&, n, !PrimeQ[#] &]]-1; t={}; Do[i=2; While[a[i]!=n, i++]; AppendTo[t, i], {n, 45}]; t (* Jayanta Basu, May 25 2013 *)

Crossrefs

Cf. A050703, A050704, A050705, A050706, A050707, A050708, A050709.

See also A050767.

Sequence in context: A065166 A006255 A110760 * A123092 A209283 A209285

Adjacent sequences: A050707 A050708 A050709 * A050711 A050712 A050713

Keyword

nonn

Author

Patrick De Geest, Aug 15 1999

Extensions

More terms from Michel ten Voorde

Status

approved