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A279623 a(n) = smallest prime factor of n-th Bell number, or 1 if there are none. 2
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, 47, 5, 2, 3, 11, 2, 5694673, 3, 2, 29, 3, 2, 6353, 3221, 2, 35742549198872617291353508656626642567, 3, 2, 5, 5, 2, 3, 7615441337805454611187, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Robert G. Wilson v, Table of n, a(n) for n = 0..100

FORMULA

a(n) = A020639(A000110(n)). - Robert Israel, Dec 25 2016

MATHEMATICA

f[n_] := (FactorInteger@ BellB@ n)[[1, 1]]; Array[f, 50, 0]

PROG

(MAGMA) [1, 1] cat [Minimum(PrimeDivisors(Bell(n))): n in [2..50]];

CROSSREFS

Cf. A000110, A020639, A139044, A144293.

Sequence in context: A302130 A156637 A195784 * A287040 A212887 A163766

Adjacent sequences:  A279620 A279621 A279622 * A279624 A279625 A279626

KEYWORD

nonn

AUTHOR

Vincenzo Librandi, Dec 25 2016

STATUS

approved

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Last modified April 23 22:17 EDT 2019. Contains 322388 sequences. (Running on oeis4.)