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A253705
Indices of primes in the 8th-order Fibonacci number sequence, A079262.
3
9, 17, 25, 125, 350, 1322, 108935, 199528
OFFSET
1,1
COMMENTS
a(9) > 2*10^5.
LINKS
Tony D. Noe and Jonathan Vos Post, Primes in Fibonacci n-step and Lucas n-step Sequences, J. of Integer Sequences, Vol. 8 (2005), Article 05.4.4
MATHEMATICA
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
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 *)
PROG
(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
KEYWORD
nonn,more
AUTHOR
Robert Price, Jan 09 2015
STATUS
approved