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Smallest Fibonacci number not less than the n-th prime.
3

%I #8 Apr 22 2018 08:47:01

%S 2,3,5,8,13,13,21,21,34,34,34,55,55,55,55,55,89,89,89,89,89,89,89,89,

%T 144,144,144,144,144,144,144,144,144,144,233,233,233,233,233,233,233,

%U 233,233,233,233,233,233,233,233,233,233,377,377

%N Smallest Fibonacci number not less than the n-th prime.

%e a(4) = 8 because the 8 is the smallest Fibonacci number not less than 7 (the 4th prime).

%t With[{fibs=Fibonacci[Range[20]]},Table[SelectFirst[fibs,#>=n&],{n,Prime[ Range[60]]}]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Apr 22 2018 *)

%o (PARI) a(n) = {p = prime(n); i = 0; until ((f = fibonacci(i)) >= p, i++); f;} \\ _Michel Marcus_, Aug 31 2013

%Y Cf. A138182, A138185.

%K easy,nonn

%O 1,1

%A _Colm Mulcahy_, Mar 04 2008