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

8, 14, 15, 18, 22, 25, 27, 29, 39, 44, 45, 46, 47, 65, 68, 69, 90, 94, 100, 103, 104, 107, 113, 116, 124, 133, 135, 138, 157, 164, 165, 166, 167, 168, 172, 175, 177, 187, 188, 193, 207, 223, 226, 229, 233, 247, 257, 260, 263, 265, 266, 270, 273, 276, 295, 299

Offset: 1

Author

Michel Lagneau, Jun 17 2010

Keywords

• nonn
• base

Examples

			8 is in the sequence because Fibonacci(8)=21, and 2^2 + 1^2 = 5 prime ;
14 is in the sequence because Fibonacci(14)=377,and 3^2 + 7^2 + 7^2 = 107 prime.
		

Crossrefs

Cf. A000045

Programs

Maple

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:

Mathematica

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