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A080469
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Composite n such that binomial(3*n,n)==3^n (mod n).
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5
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OFFSET
| 1,1
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COMMENTS
| If p is prime, binomial(3*p,p)==3^p (mod p)
No other terms below 10^9.
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LINKS
| Max Alekseyev, PARI scripts for various problems
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EXAMPLE
| 57 is a term because binomial(3*57, 57) = 12039059761216294940321619222324879408784636200 mod 57 = 27 == 3^57 mod 57.
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MATHEMATICA
| Do[If[ !PrimeQ[n], k = Binomial[3*n, n]; m = 3^n; If[Mod[k, n] == Mod[m, n], Print[n]]], {n, 1, 70000}] (Propper)
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CROSSREFS
| Cf. A109641, A109642.
Sequence in context: A124941 A116321 A187989 * A066505 A039419 A043242
Adjacent sequences: A080466 A080467 A080468 * A080470 A080471 A080472
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KEYWORD
| nonn,more,hard
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AUTHOR
| Benoit Cloitre (benoit7848c(AT)orange.fr), Oct 15 2003
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EXTENSIONS
| One more term from Ryan Propper (rpropper(AT)stanford.edu), Aug 12 2005
Four new terms added by Max Alekseyev (maxale(AT)gmail.com), Nov 05 2009
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