A050779 Primes that are not ending primes after the iterated procedure of 'composite added to the sum of its prime factors reaches a prime'.

2, 3, 5, 7, 13, 37, 43, 61, 67, 73, 97, 101, 137, 139, 157, 163, 173, 181, 193, 197, 199, 211, 223, 233, 257, 277, 281, 283, 307, 347, 349, 353, 367, 379, 389, 397, 409, 421, 433, 457, 463, 487, 499, 547, 557, 563, 577, 601, 613, 617, 641, 643, 661, 673, 677

Offset

1,1

Links

Table of n, a(n) for n=1..55.

Mathematica

a[n_]:=NestWhile[#+Total[Times@@@FactorInteger[#]]&, n, !PrimeQ[#]&]; t={}; Do[If[!PrimeQ[n], AppendTo[t, a[n]]], {n, 4, nn=678}]; Complement[Prime[Range[PrimePi[nn]]], Select[Union[t], #<nn&]] (* Jayanta Basu, Jun 01 2013 *)

Crossrefs

Cf. A050778, A050703-A050710.

Sequence in context: A249692 A140768 A192578 * A052291 A256072 A072826

Adjacent sequences: A050776 A050777 A050778 * A050780 A050781 A050782

Keyword

nonn

Author

Patrick De Geest, Sep 15 1999

Status

approved