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 A109769 Composite n such that binomial(7*n, n) == 7^n (mod n). 2
 18, 25, 133, 2107, 4676, 226037, 4477739, 827867201 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS No other terms below 10^9. LINKS Max Alekseyev, PARI/GP scripts for various problems EXAMPLE 18 is a term because binomial(7*18, 18) = 2797093093529137508875, 7^18 = 1628413597910449 and 2797093093529137508875 mod 18 = 1628413597910449 mod 18 = 1. MATHEMATICA Do[If[ !PrimeQ[n], If[Mod[Binomial[7*n, n], n] == Mod[7^n, n], Print[n]]], {n, 2, 20000}] CROSSREFS Cf. A080469. Sequence in context: A003300 A245022 A248111 * A229967 A212049 A212052 Adjacent sequences:  A109766 A109767 A109768 * A109770 A109771 A109772 KEYWORD more,nonn AUTHOR Ryan Propper, Aug 13 2005 EXTENSIONS 226037 from Max Alekseyev, Sep 13 2009 Two more terms from Max Alekseyev, Nov 06 2009 STATUS approved

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Last modified December 10 15:09 EST 2019. Contains 329896 sequences. (Running on oeis4.)