A050709 Composites c that reach a prime after 5 iterations of c-> c+sum of prime factors of c.

49, 50, 52, 56, 84, 88, 169, 176, 180, 198, 220, 302, 322, 336, 339, 363, 364, 372, 387, 402, 406, 407, 424, 429, 434, 442, 492, 494, 508, 552, 553, 562, 589, 612, 628, 633, 650, 708, 724, 744, 760, 788, 816, 819, 843, 848, 860, 861, 862, 870, 872, 896, 918

Offset: 1

Author

Patrick De Geest, Aug 15 1999

Keywords

• nonn

Examples

			49 is a term:
Iteration 1: 49 = 7*7 so 49 + (7+7) = 49 + 14 = 63 and composite.
Iteration 2: 63 = 3*3*7 so 63 + (3+3+7) = 63 + 13 = 76 and composite.
Iteration 3: 76 = 2*2*19 so 76 + (2+2+19) = 76 + 23 = 99 and composite.
Iteration 4: 99 = 3*3*11 so 99 + (3+3+11) = 99 + 17 = 116 and composite.
Iteration 5: 116 = 2*2*29 so 116 + (2+2+29) = 116 + 33 = 149 and prime.
		

Crossrefs

Cf. A050703, A050704, A050705, A050706, A050707, A050708, A050710.

Extensions

Name edited by Michel Marcus, Oct 18 2019