A253705 - OEIS

%I #17 Apr 26 2018 12:06:47

%S 9,17,25,125,350,1322,108935,199528

%N Indices of primes in the 8th-order Fibonacci number sequence, A079262.

%C a(9) > 2*10^5.

%H Tony D. Noe and Jonathan Vos Post, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL8/Noe/noe5.html">Primes in Fibonacci n-step and Lucas n-step Sequences</a>, J. of Integer Sequences, Vol. 8 (2005), Article 05.4.4

%t a={0,0,0,0,0,0,0,1}; step=8; lst={}; For[n=step,n<=1000,n++, sum=Plus@@a; If[PrimeQ[sum], AppendTo[lst,n]]; a=RotateLeft[a]; a[[step]]=sum]; lst

%t Flatten[Position[LinearRecurrence[{1,1,1,1,1,1,1,1},{0,0,0,0,0,0,0,1},200000],_?PrimeQ]]-1 (* The program takes a long time to run *) (* _Harvey P. Dale_, Apr 26 2018 *)

%o (PARI) lista(nn) = {gf = x^7/(1-x-x^2-x^3-x^4-x^5-x^6-x^7-x^8); for (n=0, nn, if (isprime(polcoeff(gf+O(x^(n+1)), n)), print1(n, ", ")););} \\ _Michel Marcus_, Jan 12 2015

%Y Cf. A001590, A001631, A100683, A231574, A231575, A232542, A214899, A230607, A020992, A232498, A214727, A081172, A214752, A141523, A214825, A235862, A000288, A000322, A000383, A249413, A060455, A079262.

%K nonn,more

%O 1,1

%A _Robert Price_, Jan 09 2015