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A080469 Composite n such that binomial(3*n,n)==3^n (mod n). +0
5
1, 36, 57, 121, 132, 552, 8397 (list; graph; listen)
OFFSET

1,2

COMMENT

If p is prime, binomial(3*p,p)==3^p (mod p)

No more terms through 70000. - Ryan Propper (rpropper(AT)stanford.edu), Aug 12 2005

EXAMPLE

57 is a term because binomial(3*57, 57) = 12039059761216294940321619222324879408784636200 mod 57 = 27 == 3^57 mod 57.

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)

CROSSREFS

Cf. A109641, A109642.

Sequence in context: A050691 A124941 A116321 this_sequence A066505 A039419 A043242

Adjacent sequences: A080466 A080467 A080468 this_sequence A080470 A080471 A080472

KEYWORD

nonn

AUTHOR

Benoit Cloitre (benoit7848c(AT)orange.fr), Oct 15 2003

EXTENSIONS

One more term from Ryan Propper (rpropper(AT)stanford.edu), Aug 12 2005

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Last modified July 6 17:22 EDT 2008. Contains 140988 sequences.


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