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%I #27 Dec 01 2022 10:52:15
%S 1,2,2,2,4,3,3,2,3,4,6,6,3,2,3,2,8,4,5,8,3,2,5,6,6,3,2,8,6,6,4,4,4,3,
%T 5,7,5,2,3,2,14,4,7,7,8,9,3,2,5,5,4,12,4,4,2,3,8,7,12,3,3,6,4,10,3,9,
%U 13,2,7,7,2,3,5,8,2,3,13,10,10,4,19,4,13,3
%N Position of p in the factorization (without multiplicity) of 2^(p-1)-1, where p is the n-th odd prime.
%H Amiram Eldar, <a href="/A358527/b358527.txt">Table of n, a(n) for n = 1..196</a>
%e a(19) = 5 because the 19th odd prime is 71 and 71 is the 5th largest distinct prime factor of 2^(71-1)-1 = 1180591620717411303423 = 3 * 11 * 31 * 43 * 71 * 127 * 281 * 86171 * 122921.
%t Array[FirstPosition[FactorInteger[2^(# - 1) - 1], #][[1]] &[Prime[# + 1]] &, 50] (* _Michael De Vlieger_, Nov 27 2022 *)
%o (PARI) a(n) = my(p=prime(n+1), v=factor(2^(p-1)-1)[,1]); vecsearch(v, p); \\ _Michel Marcus_, Nov 28 2022
%Y Cf. A065091, A098102, A358699.
%K nonn
%O 1,2
%A _G. L. Honaker, Jr._, Nov 20 2022
%E More terms from _Amiram Eldar_, Nov 23 2022
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