%I #7 Jul 03 2022 09:14:58
%S 2,3,4,7,15,26,31,43,98,117,140,215,540,1945,22279,38459,39461,66869,
%T 69328,4047994,4615259,5617480,5898979,9685120,9751023
%N Numbers k > 1 such that A354833(k) = k * A354833(k-1).
%C This sequence gives indexes of multiplicative steps in A354833.
%e For k = 7:
%e - A354833(7) = 91 = 7 * 13 = 7 * A354833(6),
%e - so 7 is a term.
%o (PARI) { seen = Map(); v = 1; for (n=2, oo, mapput(seen, v, 0); v=if (mapisdefined(seen, w=v-n) || w<0, print1 (n", "); v*n, w)) }
%o (Python)
%o from itertools import count, islice
%o def agen():
%o an, seen = 1, {1}
%o for n in count(2):
%o t = an - n
%o if t not in seen and t >= 0: an = t
%o else: an *= n; yield n
%o seen.add(an)
%o print(list(islice(agen(), 25))) # _Michael S. Branicky_, Jul 02 2022
%Y Cf. A354833.
%K nonn,more
%O 1,1
%A _Rémy Sigrist_, Jul 02 2022
%E a(20)-a(25) from _Michael S. Branicky_, Jul 02 2022