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A195758
Lesser prime factor of n-th Blum number.
6
3, 3, 3, 3, 7, 3, 3, 7, 3, 7, 3, 3, 11, 3, 7, 3, 3, 11, 7, 3, 3, 7, 11, 3, 3, 7, 3, 19, 3, 7, 11, 3, 7, 3, 11, 3, 7, 3, 7, 19, 3, 3, 11, 3, 3, 23, 3, 7, 11, 7, 3, 11, 3, 3, 19, 3, 11, 7, 19, 11, 7, 3, 3, 7, 23, 3, 3, 7, 3, 23, 3, 19, 11, 3, 7, 3, 7, 11, 7, 3
OFFSET
1,1
COMMENTS
a(n) * A195759(n) = A016105(n); a(n) < A195759(n);
a(n) = A020639(A016105(n)).
LINKS
Wikipedia, Blum integer
MATHEMATICA
Take[Transpose[SortBy[{#[[1]], #[[2]], #[[1]]#[[2]]}&/@With[{c=Select[ 4*Range[ 0, 200]+3, PrimeQ]}, Subsets[c, {2}]], Last]][[1]], 90] Harvey P. Dale, May 20 2012
PROG
(Haskell)
a195758 = a020639 . a016105
CROSSREFS
Cf. A096916.
Sequence in context: A320846 A277515 A247202 * A304684 A079084 A092323
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Sep 23 2011
STATUS
approved