login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A191375 Primes that are the sum of squares of three positive Fibonacci numbers. 0
3, 11, 17, 19, 43, 59, 137, 179, 347, 443, 449, 467, 491, 509, 569, 619, 883, 907, 1051, 1229, 1601, 2753, 3203, 3467, 3491, 3907, 6491, 8363, 8387, 8803, 20749, 20809, 21893, 24917, 28661, 41641, 44497, 49393, 54323, 55171, 62219, 75029, 108587, 284267, 372173 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
a(n) > exp(n^(1/3)*log(phi+1))/5. - Charles R Greathouse IV, Feb 24 2023
EXAMPLE
43 = fib(3)^2 + fib(3)^2 + fib(5)^2 is prime.
MATHEMATICA
f = Union[Table[Fibonacci[n]^2, {n, 16}]]; t = Union[Flatten[Table[ f[[i]] + f[[j]] + f[[k]], {i, Length[f]}, {j, i, Length[f]}, {k, j, Length[f]}]]]; Select[t, # <= f[[-1]] && PrimeQ[#] &] (* T. D. Noe, Jun 03 2011 *)
PROG
(PARI) list(lim)=my(f=List(), v=List()); for(n=1, oo, my(t=fibonacci(n)^2); if(t+2>lim, break); listput(f, t)); for(i=1, #f, for(j=1, i, for(k=1, j, my(p=f[i]+f[j]+f[k]); if(p>lim, break); if(isprime(p), listput(v, p))))); Set(v) \\ Charles R Greathouse IV, Feb 24 2023
CROSSREFS
Sequence in context: A369171 A309581 A291277 * A260793 A057179 A322962
KEYWORD
nonn,easy
AUTHOR
Carmine Suriano, Jun 01 2011
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 28 05:02 EDT 2024. Contains 371235 sequences. (Running on oeis4.)