A050708 Composites c that reach a prime after 4 iterations of c-> c+sum of prime factors of c.

32, 62, 63, 64, 69, 77, 98, 100, 102, 105, 110, 117, 171, 182, 186, 190, 195, 200, 217, 230, 234, 240, 246, 248, 270, 324, 354, 381, 388, 392, 400, 405, 410, 430, 436, 438, 444, 455, 456, 474, 481, 482, 483, 490, 528, 540, 568, 576, 582, 584, 598, 605, 625

Offset

1,1

Links

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

Example

182 is a term:
Iteration 1: 182 = 2*7*13 so 182 + (2+7+13) = 182 + 22 = 204 and composite.
Iteration 2: 204 = 2*2*3*17 so 204 + (2+2+3+17) = 204 + 24 = 228 and composite.
Iteration 3: 228 = 2*2*3*19 so 228 + (2+2+3+19) = 228 + 26 = 254 and composite.
Iteration 4: 254 = 2*127 so 254 + (2+127) = 254 + 129 = 383 and prime.

Crossrefs

Cf. A050703, A050704, A050705, A050706, A050707, A050709, A050710.

Sequence in context: A130447 A116284 A138555 * A132300 A206371 A255561

Adjacent sequences: A050705 A050706 A050707 * A050709 A050710 A050711

Keyword

nonn

Author

Patrick De Geest, Aug 15 1999

Extensions

Name edited by Michel Marcus, Oct 18 2019

Status

approved