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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
OFFSET
1,1
COMMENTS
No other terms below 10^9.
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: A245022 A362435 A248111 * A350773 A229967 A212049
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