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A080214
Binomial(greatest prime factor of n, smallest prime factor of n).
2
1, 1, 1, 1, 1, 3, 1, 1, 1, 10, 1, 3, 1, 21, 10, 1, 1, 3, 1, 10, 35, 55, 1, 3, 1, 78, 1, 21, 1, 10, 1, 1, 165, 136, 21, 3, 1, 171, 286, 10, 1, 21, 1, 55, 10, 253, 1, 3, 1, 10, 680, 78, 1, 3, 462, 21, 969, 406, 1, 10, 1, 465, 35, 1, 1287, 55, 1, 136, 1771, 21, 1, 3, 1, 666, 10
OFFSET
1,6
LINKS
MATHEMATICA
a[n_] := With[{f = FactorInteger[n]}, Binomial[f[[-1, 1]], f[[1, 1]]]];
Array[a, 100] (* Jean-François Alcover, Dec 02 2021 *)
PROG
(PARI) A080214(n) = if(1==n, n, my(f = factor(n), lpf = f[1, 1], gpf = f[#f~, 1]); binomial(gpf, lpf)); \\ Antti Karttunen, Sep 06 2018
CROSSREFS
KEYWORD
nonn,look
AUTHOR
Reinhard Zumkeller, Feb 06 2003
STATUS
approved