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%I #9 Dec 14 2023 16:30:01
%S 3,4,4,10,17,8,25,5,28,9,81,13,289,64,100,41,6561,31,6657,57,529,1025
%N a(n) is the smallest number k > 1 such that bigomega(k^n - 1) = n.
%C a(23) <= 196609; a(24) = 79; a(25) <= 28561; a(26) = 14015; a(27) = 961; a(28) = 729; a(30) = 361; a(32) = 2047.
%e a(5) = 17 is the smallest number of the set {k(i)} = {17, 19, 21, 26, 27, 39, 45, ...} where k(i)^5 - 1 has exactly 5 prime factors counted with multiplicity.
%o (PARI) a(n) = my(k=2); while (bigomega(k^n-1) != n, k++); k;
%Y Cf. A001222, A219019, A241793, A359070.
%K nonn,more,hard
%O 1,1
%A _Daniel Suteu_, Dec 14 2023