Also by hand, so please check 1 2 4 3 6 5 12 7 20 9 8 21 24 10 16 25 18 ... the sequence of primes may be of interest (1) 5 17 29 59 89 173 229 409 499 587 839 1151 1291 1531 1931 2237 ... R. On Fri, 13 Feb 2004, Leroy Quet wrote:

Let a(1) = 1;

Let a(m) be the lowest yet unpicked positive integer such that:

sum{k=1 to m} k* a(k)

is a prime.

Figured by hand, so very well could be wrong, I get:

a(k) : 1, 2, 4, 3, 6, 5, 12, 7,...

Question: Is this a permutation of the positive integers?

If so, its inverse-permutation is:

1, 2, 4, 3, 6, 5, 8,...

(I get some EIS matches for the few terms I give for the inverse permutation, but no matches for the primary sequence.)

thanks,