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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..65537

MATHEMATICA

a[n_] := With[{f = FactorInteger[n]}, Binomial[f[[-1, 1]], f[[1, 1]]]];

Array[a, 100] (* Jean-Fran├žois 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

Cf. A006530, A020639, A080215, A080211.

Sequence in context: A340149 A340075 A307847 * A263383 A185620 A096066

Adjacent sequences:  A080211 A080212 A080213 * A080215 A080216 A080217

KEYWORD

nonn,look

AUTHOR

Reinhard Zumkeller, Feb 06 2003

STATUS

approved

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Last modified May 25 19:19 EDT 2022. Contains 354071 sequences. (Running on oeis4.)