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%I #25 Sep 08 2022 08:46:18
%S 1,1,2,5,3,2,7,877,2,3,5,2,37,27644437,2,5,241,2,7,271,2,3,3,2,3,13,2,
%T 47,5,2,3,11,2,5694673,3,2,29,3,2,6353,3221,2,
%U 35742549198872617291353508656626642567,3,2,5,5,2,3,7615441337805454611187,2
%N a(n) = smallest prime factor of n-th Bell number, or 1 if there are none.
%H Amiram Eldar, <a href="/A279623/b279623.txt">Table of n, a(n) for n = 0..131</a> (terms 0..100 from Robert G. Wilson v)
%F a(n) = A020639(A000110(n)). - _Robert Israel_, Dec 25 2016
%t f[n_] := (FactorInteger@ BellB@ n)[[1, 1]]; Array[f, 50, 0]
%o (Magma) [1,1] cat [Minimum(PrimeDivisors(Bell(n))): n in [2..50]];
%Y Cf. A000110, A020639, A139044, A144293.
%K nonn
%O 0,3
%A _Vincenzo Librandi_, Dec 25 2016
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