A050709 - OEIS

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

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..53.

EXAMPLE

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.