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A178838 Indices n such that the sums of the squares of the digits of Fibonacci(n) are prime. 0

%I

%S 8,14,15,18,22,25,27,29,39,44,45,46,47,65,68,69,90,94,100,103,104,107,

%T 113,116,124,133,135,138,157,164,165,166,167,168,172,175,177,187,188,

%U 193,207,223,226,229,233,247,257,260,263,265,266,270,273,276,295,299

%N Indices n such that the sums of the squares of the digits of Fibonacci(n) are prime.

%e 8 is in the sequence because Fibonacci(8)=21, and 2^2 + 1^2 = 5 prime ;

%e 14 is in the sequence because Fibonacci(14)=377,and 3^2 + 7^2 + 7^2 = 107 prime.

%p with(combinat, fibonacci):nn:= 120: for n from 1 to 700 do:p:=fibonacci(n):l:=length(p):n0:=p:s:=0:for m from 1 to l do:q:=n0:u:=irem(q, 10):v:=iquo(q, 10):n0:=v :s:=s+u^2:od:if type(s, prime)=true then printf(`%d, `, n): else fi:od:

%t Flatten[Position[Fibonacci[Range[300]],_?(PrimeQ[Total[ IntegerDigits[ #]^2]]&), {1},Heads->False]] (* _Harvey P. Dale_, Aug 31 2014 *)

%Y Cf. A000045

%K nonn,base

%O 1,1

%A _Michel Lagneau_, Jun 17 2010

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Last modified October 4 03:23 EDT 2022. Contains 357237 sequences. (Running on oeis4.)