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A050710 Smallest composite that when added to sum of prime factors reaches a prime after n iterations. 29
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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
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
See also A050767.
Sequence in context: A065166 A006255 A110760 * A123092 A209283 A209285
KEYWORD
nonn
AUTHOR
Patrick De Geest, Aug 15 1999
EXTENSIONS
More terms from Michel ten Voorde
STATUS
approved

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Last modified June 21 08:06 EDT 2024. Contains 373543 sequences. (Running on oeis4.)