A053093 Smallest composite which when sum of prime factors is repeatedly subtracted reaches a prime after n iterations.

8, 16, 27, 58, 104, 150, 186, 256, 324, 378, 576, 636, 805, 1470, 1520, 1564, 1612, 3478, 3864, 8022, 9996, 10548, 11573, 11946, 12006, 13587, 13640, 15156, 20504, 21204, 21252, 24017, 24080, 25823, 27989, 30067, 30866, 31165, 31212, 47628

Offset

1,1

Links

Paolo P. Lava, Table of n, a(n) for n = 1..100

Example

a(5)=104. Iteration 1: 104=2*2*2*13 and sum of factors is 19; 104-19=85. Iteration 2: 85=5*17; 85-22=63. Iterations 3,4,5 produce 63-13=50, 50-12=38 and 38-21=17, a prime.

Crossrefs

A050710, A053094.

Sequence in context: A246549 A076405 A099997 * A175086 A348231 A331490

Adjacent sequences: A053090 A053091 A053092 * A053094 A053095 A053096

Keyword

nonn

Author

Enoch Haga, Feb 28 2000

Status

approved