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A112874
Numbers n such that the coefficient of x^n in (x^2-x-1)^n is prime.
0
3, 4, 5, 6, 7, 10, 11, 12, 26, 160, 3787, 31877
OFFSET
1,1
COMMENTS
n=31877 yields a probable prime; the others have been proved prime. These n were also found by Eric Weisstein, who found no other n<100000.
LINKS
Eric Weisstein's World of Mathematics, Central Trinomial Coefficient
Eric Weisstein's World of Mathematics, Integer Sequence Primes
MATHEMATICA
Select[Range[200], PrimeQ[Coefficient[Expand[(x^2-x-1)^# ], x, # ]]&]
CROSSREFS
Cf. A098331 (coefficient of x^n in (x^2-x-1)^n).
Sequence in context: A047308 A092860 A351392 * A159973 A359772 A158008
KEYWORD
hard,nonn
AUTHOR
T. D. Noe, Sep 29 2005
STATUS
approved